NATIONAL CENTER Series 21 

For HEALTH STATISTICS Number 3 

VITAL and HEALTH STATISTICS
 .


DATA FROM THE NATIONAL VITAL STATISTICS SYSTEM 

Weight at Birth and 

Survival of the Newborn 

United States, Early 1950 

Statistics derived from vital records on neonatal mortality by weight at birth and gestation, age, by color 

and sex, to infants born in the United States during 

the first 3 months of 1950. 

Washington, D.C. duly 1965 

U.S. DEPARTMENT OF 

HEALTH, EDUCATION , AND WELFARE Public Health Service . 

Anthony J. Celebrezze Luther L. Terry 

Secretary Surgeon Generol 
This report was originally published in Vital Statistics—Special Repovts, 

Vol. 39, No. 1 (July 1954). Since the data presented and analyzed in the 

report are of continuing importance, it has been reprinted in Vital and 

Health Statistics without change. 

. .. .,,, ,,, ,., , ... , . 

Public Health Service Publication No. 1000-Series 21-No. 3 
NATIONAL CENTER FOR HEALTH STATISTICS 

FORREST E. LINDER, PH. D., Director 

THEODORE D.WOOLSEY,Deputy Director 

OSWALD K.SAGEN,PH.D.,ysnkmt Director 

WALT R.SI,MMONS,
MA.,statistical Advi~or 

ALICEM.WATERHOUSE, M.D.,Medical Advisor 

,, JAMES E.-KELLY, D.D,S.,
Dental Advijor ,. LOUISR.STOLCIS,
MA,,Executive O@cer 

DIV1S1ON OF VITAL STATISTICS 

ROBERT D. GROVE, PH. D., Chief 

ANDERS S, LUNDE, PH. D., A~irtant Chief 

Public Health Service Publication No. 1000-Series 21-No. 3 
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CONTENTS


Page 

Introduction--------------------------------

Source of data -------------------------

Registration completeness 

Classification 

Seasonality 

Distribution of n?t stated 

and gestation.a@m 

Chance variation 

Distributions of live’births 

Birth weight ------=<------------------

Ge#&ien and%iW@ weight 

5


5


5


6


6


6


7


8


8


10


Page 

Neonatal deaths ---------------------------- 14 

~-fih weight 14 

tiestation” 17 

Gestation and birth weight--------------- 17 

+ttendant at birth 18 

Weight distribution and neonatal 

mortali~ 19 

Single births in hospitals 22 

Summary 24 

References 25 

TEXT TABLES 

Table Page 

A. Percent of live births and neonatal deaths with birth weight a.qd gestation not stated 

United States, January 1 to March 31, 1950------------------------------------------------ 7 

B. Birth weight statistics for single live births, by race, under alternative methods for 

distributing not stated birth weights: United States, January 1 to March 31, 1950 ---------- 8 

c. Percent distribution of live births, by birth weight, race, sex, and plurality 

United States, January 1 to March 31, 1950------------------------------------------------ 9 

D. Percent distribution of live births by weeks of gestation, race, sex, and pluiality: 

United States, January 1 to March 31, 1950------------------------------------------------ 12 

E. Percent distribution of live ,births by birth weight, weeks of gestatim, race, and pku ality: 

United States, January 1 to Max’ch 31, 1950------------------------------------------------ 13 

F. Median weights of live births by weeks of gestation, race, sex, and plurality: 

United States, January 1 to March 31, 1950------------------------------------------------ 14 

\ G. Neonatal gmtality rates by birth weight, race, sex, and plurality United States, 

January 1 to March 31, 1950--------------------------------------------------------------- 15 

H.	 Neonatal mortality rates by weeks of gestation, race, sex, and plurali~. United 

States, January 1 to March 31, 1950 17 

I. 1Neonatal mortality rates by birth weight, weeks of gestation, and race: United States, 

January 1 to March 31, 1950--------------------------------------------------------------- 18 

J. Neonatal mortality rates by birth weight, weeks of gestation, race, and sex: 

United States, January 1 to March 31, 1950------------------------------------------------ 19 

K.	 Percent distribtuion of live births and neonatal mortality rates, by birth weight, 

race, and attendant at birt.k United States, January 1 to March 31, 1950 20 

L. Neonatal mortality rates among births in hospitals and not in hospitals, by birth 

weight, race, and plurality: United States, January 1 to March 31, 1950-------------------- 22 

M. Neonatal mor”~lity rates gong single births in hospitals, by detailed birth weight 

and race: United States, January 1 to March 31, 1950-------------------------------------- 22 

3 
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4 CONTENTS 

Table GENERAL TABLES 

1.	 Live birtheamd neonatal deaths, by birth weight, race, sex, andplurali~ Page 

United States, January lto March 31, 1950------------------------------------------------ 26 

2.	 Live births by birth weight, weeks of gestation, race, sex, and plurality: 

United States, January 1 to March 31, 1950------------------------------------------------ ‘27 

3.	 Neonatal deaths by birth weight, weeks of gestation, race, sex, and plurality: 

United States, January 1 to March 31, 1950------------------------------------------------ 29 

4.	 Live births and neonatal deaths, by birth weight, race, and attendant at birth 

United States, January 1 to March 31, 1950------------------------------------------------ 31 

5.	 Live births and neonatal deaths, by birth weight, race, attendant at birth, and 

plurality: United States, January 1 to March 31, 195& ------------------------------------- 32 

6.	 Single live births in hospitals and neonatal deaths among this group, by detailed birth 

weight and race: United States, January 1 to March 31, .195@------l 33 

FIGURES 

Figure Page 

1. Birth weight distribution of “five births: United States, January 1 to March 31, 1950-------- 11 

2.	 Neonatal mortality rates by birth weighk United States, January 1 to 

March 31, 195& 16 3.	 Neonatal mortality rates among single births in hospitals, by detailed birth weight 

and race: United States, January 1 to March 31, 1950 ------------------------------------ 23 

4.	 Neonatal mortality rates among single white births in hospitals, by detailed birth 

weight and specified gestation groups: United States, January 1 to March 31, 1950 ------- 24 
Weight at Birth and its Effeat on Survival of the 

Newborn in the United States, Early 1950 

Sam Shap ire, Cliief of the Natal ity Analysis Branch, and Jeanne Unger, Analytical Statistician


INTRODUCTION 

Early infancy has always been an extremely 

hazardous period to survive. Although great progress 

has been made in reducing the loss during this difficult 

period, it has lagged behind the success in later infancy. Over the past 35 years, mortality has been cut 

in half in the first few’ weeks of life, while in the 

balance of the first year, the rate has been reduced to 

a fifth of what it was. Today, two-thirds of the infant 

deaths occur in the neonatal period—i. e., within 4 

weeks after birth-and in most of these cases, immaturity is cited by the physician as a factor. 

The need for information on the risk of mortality 

among babies born at different levels of maturity has 

long been recognized as an essential feature of programs directed at the immaturity problem. Special 

studies by individual hospitals and by a number of 

city and State departments of health have contributed 

greatly to meeting this need. With the addition of 

items on “birth weight” and “weeks of gestation” to 

practically all State certificates of birth in 1949, the 

development of data for other areas and for the nation 

as a whole has become a practical matter. 

This report presents nationwide statistics on birth 

weight derived from vital records for babies born 

between January 1 and March 31, 1950, and for neonatal deaths among this group. The information is 

shown by race, sex, plurality of birth, and attendant 

at birth. Future reports will present birth weight 

statistics for broad geographic areas, and will consider the relationship between birth weight and such 

variables as birth order; age and previous fetal loss 

of the mother; age at death; and cause of death. The 

subject of fetal loss will also be considered in relation 

to neonatalmortality. 

Although birth weight is used as the princip~ 

measure of maturity level at birth, a limited amount 

of gestation age statistics is introduced in this report. 

Despite serious errors in the birth record information 

on gestation age, the data contribute to the int~pr etation of a number of the differentials in mortality 

experience indicated by the birth weight variable. 

Improvement in reporting gestation age would greatly 

broaden the possibilities for investigating, statistically, factors that affc%t the survival of the newborn. That it is possible to obtain reasonably sound 

series of gestation age data has already been demonstrated by others. 

Source of ciata 

Matched birth and death records for infants born 

during the first quarter of 1950 who died”within 28 

days after birth were used to obtain the mortality data 

shown in this report. The matching ,of these records 

was incidental to carrying out an unrelated project, 

the 1950 birth registration test. When the matching 

was completed, punched cards combining information 

from corresponding birth and death records were 

prepared for the infants who died. Data from birth 

records for children born during January-March 1950. 

formed the basis for developing the weight distributions present@ and served as the denominators for 

the mortality rates. Birth and death certificates relating to children born to,.residents of Massachusetts 

were excluded from all tabulations since this State 

did not require the reporting of birth weight. 

Matching birth certificates were not found for a 

small proportion (2.4 percent) of the neonatal death 

records filed. In the white group 2.0 percent and in 

the nonwhitegroup 4.6 percent of tie deaths, were not 

matched., With regard to age at death, the proportions 

of unmatchedcertificates were higher for infants dying 

at under 1 hour and at 5 through 27 days than at the 

intervening ages, but this proportion was small in all 

cases, never exceeding 5.8 percent. The unmatched 

group was also somewhat biased as to cause of death, 

there being greater proportions for which the cause 

was, pneumonia, homicide, or not stated than in the 

total death group. 

In compiling the data for this report, all of the 

“unmatched:’ deafi certificates were included and a 

“matching” birth certificate was created for each by 

using data on the deathcertificates for certain personal particulars. This treatment of the unmatched ~oup 

was decided upon because of the different procedures 

followed in the States with respect to obtaining birth 

certificates for the group. Some States routinely 

match birth and infant death records and take steps 

to have birth-records placed on file in those cases 

where the matching birth records cannot be found. 

As a result of this procedure, virtually all of the 

neonatal death records filed in these States are 

matched. In the other areas, the proportions of unmatched records are generally much greater. Thus, 

by means of including rather” than excluding all qnmatched death records, a degree of comparability is 

achieved. This will be of especial significance for 

a later report where geographic data are shown. 

Re@stration completeness 

The data in this report are derived from records 

for registered events (except for the group discussed 

above). A test of registration completeness for 1950 

indicated that practically all (98.6 percent) of the 

white births and 93.5 percent of the nonwhite were 

registered. No definitive information is available 

on the completeness of death registration, but it js 

5 
6 VITAL STATISTICS-SPECIAL REPORTS 

thought to vary generally as birth registration corn-” 

pleteness. In some instances where infants die 

immediately after birth, it is probable that neither 

a live birth nor a death certificate is filed. A number 

of these infants may be reported as fetai deaths, 

while others may not be reported at all. This situation 

is undoubtedly of relatively greater importance at the 

very low birth weights than at the higher weights, and 

might lead to an understatement of the proportions of 

infants at the low weights and also to an understatement of the mortality rates among these children. 

Classification 

In almost all of the areas, birth weight was reported in terms of pounds and ounces. The traditional 

gram groupings, however, have been used to tabulate 

and present the data in order to facilitate comparison 

with the results from other studies of this type. The 

equivalents of these groupings in terms of pounds and 

ounces are as follows: 

1,000 grams or less = 2 lb. 3 oz. or less 

1,001-1,250 grams = 2 lb. 4 OZ.-2lb. 12 OZ. 

1,251-1,500 grams = 2 lb. 13 OZ.-3 lb. 4 OZ. 

1,501-1,750 grams = 3 lb. 5 OZ.-3 lb. 13 OZ. 

1,751-2,000 grams = 3 lb. 14 oz.-4 lb. 6 OZ. 

2,001-2,250 grams = 4 lb. 7 OZ.-4 lb. 15 OZ. 

2,251-2,500 grams = 5 lb. O oz.-5 lb. 8 OZ. 

2,501-2,750 grams = 5 lb. 9 oz.-6 lb. 1 OZ. 

2,751-3,000 grams = 6 lb. 2 oz.-6 lb. 9 OZ. 

3,001-3,500 grams = 6 lb. 10 oz.-7 lb. 11 OZ. 

3,501-4,000 grams = 7 lb. 12 oz.-8 lb. 13 OZ. 

4,001-4,500 grams = 8 lb. 14 OZ.-9lb. 14 OZ. 

4,501 gmms or rmre = 9 lb. 15 oz. or more 

The birth records for 1950 in all but a few of the 

Stat es requested gestation age information in the 

following form: “Length of pregnancy -weeks.” In 

practice, period of gestation is generally interpreted 

as referring to number of completed weeke that have 

elapsed between the first day of the last menstrual 

period and the date of birth of the child. At the 

present time, important inaccuracies due, in part, 

id failure to carry out this computation are evident 

in the data reported. These are described in a later 

section. 

For purposes of classification, infants weighing 

2,500 grams or less at birth have been referred to as 

“immature” or “premature.” This weight criterio~ 

was recommended by the American Academy of 

Pediatrics in 1935, and later adopted in the Sixth 

Revision of the International Lists of Diseases and 

Causes of Death (1948). The term “premature,” 

although containing the concept of duration of pregnancy, has been used for many years in connection 

with the birth weight criterion. In units of gestation 

age, it relates to pregnancies of less than 37 completed weeks. It is recognized in using these terms, 

. 

that there may be basic differences in physical development for some of the subgroupings of births discussed, which would affect the general applicability 

Of the criterion for classifying births as immature 

or premature. 

Seasonality 

The proportion of children weighing 2,500 grams 

or less in the first 3 months of 1950 (7.4 percent) is 

slightly smaller than that for the year as a whole (7.6 

percent).1 The full weight distributions of white and 

nonwhite births included in the study cliffer somewhat 

from the distributions expected on the basis of data for 

the year as a whole. Although these differences are 

statistically significant (P <.001), they are of small 

enough order of magnitude not to distrub the relationships discussed in the report. 

There are also differences between the’ neonatal 

mortali~ rates for the entire year and the rates among 

births in January through March of 1950. Here too, 

however, the differences are very small. For all races 

combined, tie rate for the United States for the year is 

20.5 per 1,000 live births, while for January through 

March the rate is 19.9 for the United States and 20.0 

for the United States excluding Massachusetts. 

Distribution of not stated birth weights and 

gestation ag~ 

It was apparent from the data that birth weight 

reporting was less complete for infants born at early 

gestation ages than at a more advanced stage of the 

pregnancy cycle. To reduce this bias, gestation age 

information was used to distribute the groups that had 

no weight statements. 

Not stated birth weights were allocated by first 

distributing the not stated weights among neonatal 

deaths in each gestation group according to the distribution of the “known” weights in that group. The 

remainder of the not stated neonatal deaths which 

lacked information on period of gestation was then 

distributed by weight according to the weight distribution for all other neonatal deaths. 

For births, the group referring to’ children who 

died during the neonatal period was distributed as 

indicated above. The residual was allocated using the 

relationship of gestation and birth weight for the 

remaining group of births. 

For both births and deaths the not stated gestations were distributed proportionately within each 

weight group where this item was stated and according 

to the over-all distribution if weight was not available. 

lThe data for the first 3 months exclude births 

to residents of Massachusetts while those for the 

year as a whole exclude births to residents of 

both Connecticut and Massachusetts. However, this 

difference does not affect the conclusion. 
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Vol. 39, No. 1 WEIGHT 

Table A gives the proportions uf birth weights not 

stated among births znd neonatal deaths by race and 

plurality. The percentages af births and deaths that 

had no statement of either weight or gestation age are 

also indicated. 

Various methods for distributing the not stated 

birth weights were applied to the data in an effort to 

evaluate the effect of clifferent treatments of this 

group. It was found that the relationships discussed 

in the main body of the report were not altered by the 

choice of procedure. Results in terms of percentage 

distributions and mortality rates under each of four 

procedures (including the one used throughout this report) are shown in table B together with a description 

of the method. It will be noted that the clifferenc es 

in the statistics obtainedunder alternative procedures 

are relatively small. 

Despite the fact that a reasonably sound basis 

existed for distributing the “not stateds, ” the reader 

is cautioned not to draw conclusions from relatively 

small differences in view of the fairly large size of 

this group. An exception to this would be a $eries 

of small differences which were sll in the same direction. 

Chsnce variation 

Chance variation, in addition to the biases in reporting already discussed, must be considered in 

evaluating the data shown. This variation is related 

to the size of the birth population on which the figures 

are based and on the frequency of the occurrence 

AT BIRTH 7 

measured. The smaller the popukdion, or the smaller 

the frequency of the event in a given population group, 

the greater the relative variability.2 Mortality rates 

were not computed in the accompanying tables for 

certain small frequency groups, i. e., where the 

birth population was less than 100 and there were 

fewer than 20 deaths. 

zl.h~ ~t~~d~rd error iS the � easure used ‘0 

evaluate this variability. Chances are less than


1 in 20 that a difference as large as 2 standard


errors would srise by chsnce. Generally, the


standard error of s rate per 1, 000 births is


where R is the rate and B is the number of births 

used to compute the rate. The standard error of 

the difference between 2 rates, RI and R2, is 

If 2 rates differ by less than twice this standard


error, it is usually concluded that they are not


significantly different (statistically) . When a


rate is low and the number of deaths is very small,


the standard error of the rate is ~ where R is 

* 

the rate and ~ is the number of deaths. The standard error of the difference between 2 such rates, 

RI and R2, is 

4+4 

r ~ ~“ 

TABLE A. PESCENT OF LIVE BIRTHS AND NEOIWTALDEATHS WITH BISTE WEIGE’I’MO GESTATIONNOT S!CATEO:


UNITED STAKES, JMWMRY 1 TO MABCE 31, 1950


(Excludesdata for Massachusetts)


WEIGHT NOl! S!WIED prmm Am GESTATIONml! STATED


All All.


births Single Plural births Single Plural


All racea 

White --.---------


Iionwhite


All races


WMte


Nonwhite -----------,---------


BIRTSS


3.8 3.8 4.8 2.1 2.1 2.1 

3.2 3.2 3.8 1.9 1.9 1.6 

7.0 7.0 9.2 3..6 3.6 4.4 

NEOIWI?ALDEAms


14.7 14.8 U3.8 6.0 6.4 2.8


13.5 3.3.5 12.6 4.9 5.2 2.3


19.8 19.9 18.4 10.5 11.2 4.5

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8’ VITAL STATISTICS-SPECIAL REPORTS 

TABLE B. BIRTH WEIGBT STATISTICSFOR SINGIIELIVE BEWES, BY RACE, UNDER ALTERNATIVEMETHODSFOR DISTR.lB-


UYING NOT STATEDBIRTH WEIGH?KS:
UNITED STATES, JANUARY 1 TO MARCH 31, 1950


(Excludesdata for Massachusetts
)


1 

I NONWEIT!E 

BIRTH WEIGBT


(IN GRAMS) Method I Method I Method I Method Method Method 

A B c D A B 

PERCENIDIS’I!RIBUTION
l?BIR’TES


All weights 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 

1,000 or lef3s----------- 0.4 0.4 0.4 0.4 0.5 0.5 0.5 0.5 

1,001-1,500------------- 0.5 0.5 0.5 0.5 0.7 0.7 0.7 0.7 

1,501-2,000------------- 1.0 1.0 1.0 1.0 1.5 1.5 1.5 1.5 

2,001-2,500 4.2 4.2 4.1 4.2 5.9 5.9 5.7 5.9 

2,501-3,000------------- 17.4 17.4 17.2 17.5 20.5 20.4 19.9 20.5 

3,001-31500------------- 38.6 38.6 39.3 38.6 35.6 35.7 37.5 35.6 

3,501-4,000------------- 28.~ 28.2 27.8 28.2 24.0 24.0 23.2 24.0 

4,001-4,500------------- 7.9 7.9 7.9 7.9 7.4 7.4 7.2 7.4 

4,501 or more 1.8 1.8 1.8 1.8 3.9 3.9 3.8 3.9 

NEONATAL MORTALITYRATES 

All weights 17.3 17.3 17.3 17.3 24.4 24.4 24.4 24.4 

1,000 or less 880.2 881.4 889.8 878.2 835.2 836.1 849.2 823.6 

1,001-1,500------------- 575.0 577.4 578.5 573.3 511.0 508.0 516.0 507.4 

1,501-2,000------------- 238.4 235.9 233.9 239.6 190.0 190.9 185.1 192.2 

2,001-2,500------------- 53.5 53.2 50.4 54.4 50.0 49.7 4s.1 51.0 

2,501-3,000------------- 12.2 12.2 12.4 12.4 15.1 15.1 15.5 15.3, 

3,001-3,500------------- 6.2 6.2 6.7 6.4 9.5 9.6 10.4 9.7 

3,501-4,000------------- 4.9 5.0 4.7 5.1 10.4 10.5 10.0 10.6 

4,001-4,500------------- 6.7 6.7 6.4 6.9 12.3 1’2.6 12.0 12.7 

4,501 or more 12.1 12.1 u. 5 12.4 20.3 20.9 20.1 21.1 

mm. -The alternativescliffer onlyinthe method for allocatingthe notstatedweights for which geetat Ion ages were reported. These methods are deecribedbelow: 

A. se; text for descriptionof this method. 

B. It is assumedthat the not statedsat each geetationage fall at the median weight for that gestation 

level.


c. It Is assumedthat thereisparallelisminthe percentagedistributions
ofknown weights and gestations,


and on this basis the not statedsat each gestationage are distributedto an equatedweight group or


groups. (See reference8 for detailsof this method.)


D.	 It isassumedthat the not statedsare distributedaccordingto the generalweight distributionwithout


regard to gestationage reported.


DISTRIBUTIONS OF LIVE BIRTHS of the children that died in the neonatal period. 

The birth of a live born infant weighing 1,500


Birth weighJ grams or less was a very infrequent event (1.1 percent


of all births). Each advance towsrd higher weight


A great majori~ of the children born in the ftist brought a sharp incresse k the proportion of children 

3 months of 1950 weighed over 2,500 grams at birth. born, with the result that over two-thirds of the 

In fact, only 7.4 percent weighed 2,500 grams or less immature births fell in the weight group 2,001-2,500 

(table C). However, in this group are about two-thirds grams. 
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Vol. 39, No. 1 W EIGHT AT BIRTH 9 

‘TABLE c. PERCENT DISTRIBUTION OF LIVE BISTBS, BY BIXTE WEIGBT, RACE, SEK, AND PLOSALITY: UNITED STATES, 

JANUARY 1 TO NAROH 31, 1950 

(Births with birth weight not stated are distributed. Excludes births to residents Of Massachusetts)


AIL RACES WHITE NONWHITE 

,BIR!lTiWEIG2T


(IN GRANs) Both Both Both
 Male Female Male Female Male Female
 sexes sexes sexes


TOTAL BIRTES 

All wei@rts 100.0 100.0 100.0 100.0 100.0 100.0 .100.0 

1,000 or less--------------- 0.5 0.5 0.5 0.4 0.4 0.4 0.6 0.6 0.6 

1,001-1,500----------------- 0.6 0.6 0.6 0.6 0.6 0.6 0.s 0.8 0.9 

1,501-2, 000----------------- 1.4 1.3 1.4 1.3 1.2 1.4 1.8 1.7 2.0 

2,001-2,500----------------- 4.9 4.3 5.6 4.7 4.1 5.3 6.4 5.6 7.3 

2,501-3,000----------------- 18.1 E. .4 21.0 17.7 14.9 20.7 20.6 18.3 23.0 

3,001-3,.500----------------- 37.7 36.1 39.4 38.1 36.3 40.0 35.1 34.6 35.6 

3,501-4,000----------------- 27.L 29.8 24.2 27.7 30.5 24.7 23.5 25.5 21.5 

4,001-4,500----------------- 7.7 9.5 5.8 7.8 9.7 5.8 7.3 8.5 6.0 

4,501 or mOre--------------- 2.1 2.6 1.5 1.8 2.3 1.2 3.8 4.5 3.2 

2,500 or less 7.4 6.7 8.1 7.0 6.3 7.6 9.7 8.7 10.7 

2,501 or mere--------------- 92.6 93.3 91.9 93.0 93.7 92.4 90.3 91.3 89.3 

Median weight (in grSJU6)l--- 3,320 3,390 3,260 3,330 3,400 3,270 3,280 3,330 3,220 

SINGLE BIRT’E3 

All weights--------- 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 

1,000 or less 0.4 0.4 0.4 0.4 0.4 0.4 0.5 0.5 0.5 

1,001-1,500----------------- 0.5 0.5 0.5 0.5 0.5 0.4 0.7 0.6 0.8 

1,501-2,000----------------- 1.1 1.0 1.1 1.0 1.0 1.1 1.5 1.4 1.6 

4.4 

2,501-3,000----------------- 17’.9 15.1 20.8 17.4 14.6 20.5 20.5 18.1 22.9 

3,001-3,Soo----------------- 38.2 36.5 40.0 38.6 36.7 40.6 35.6 35.1 36.2 

3,501-4,000----------------- 27.6 30.3 24.7 28.2 31.0 25.1 24.0 26.0 21.9 

4,001-4,500----------------- 7.8 9.7 5.9 i’. 9 9.8 5.9 7.4 8.7 6.1 

4,501 or more--------------- 2.1 2.7 1.5 l..e 2.4 1.2 3.9 4.6 3.2 

2,500 or less--------------- 6.4 5.8 7.1 6.0 5.5 6.6 8.6 7.6 9.6 

2,501 or mere--------------- 93.6 94.2 92.9 94.0 94.5 93.4 91.4 92.4 90.4 

2,001-2,500-----------------T 3.8 5.1 4.2 3.6 4.s 5.9 5.1 6.7 

Median weight(in gmms)=--- 3,330 3,400 3,270 3,340 3,410 3,280 3,290 3,340 3,240 

BIRTHS lliPLURAL S13TS


A1l. weights 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 

II 1,000 or lese 4.0 3.9 4.1 3.9 3.8 4.1 4.2 4.4 4.0 

1,001-1,500----------------- 5.6 5.0 6.1 5.4 4.8 6.1 6.1 5.9 6.3 

1,501-2,000----------------- 14.2 12.6 15.9 14.2 12.3 16.0 14.5 13.7 15.3 

2,001-2,500----------------- 29.2 28.1 30.4 29.2 28.2 30.2 29.2 27.3 31.3 

2,501-3,000----------------- 29.5 30.2 28.7 29.9 30.8 29.1 27.1 27.1 27.2 

3,001-3,500----------------- 14.1 16.1 12.0 14.2 16.2 12.1 13.4 15.3 SL.3 

3,501-4,000----------------- 2.8 3.5 2.1 2.5 3.2 1.9 4.0 4.7 3.2 

4,001-4,500----------------- 0.6 0.6 0.6 0.5 0.5 0.5 1.2 1.2 1.2 

4,501 or mOre--------------- 0.1 0.1 0.1 0.0 0.1 0.0 0.3 0.4 0.3 

2,500 or less--------------- 53.0 I 49.5 56.5 52.8 49.2 56.4 54.0 

2,501 or mere--------------- 47.0 50.5 43.5 47.2 50.8 43.6 46.0 

51.3 

4s.”7 

56.8 

43.2 

Median wei@t (in grems)l--- 2,400 2,460 2,520 2,400 2,440 2,4s0 2,400 

lComputed to nearest 10 grams on basis of original reporting units of pouuds and ounces. 

NOII1.
-Percentages for summary gcoupa were independently computed ead therefore do not necessarily equal exactly


the sum of the individual component groups.


788-367O-65—2

10 VITAL STATISTICS-SPECIAL REPORTS 

The area of. peak concentration of births was 

between 2,501 and 4,000 grams. The first 500-gram 

group in this interval (2,501-3,000) contained 18 percent of all births, while almost two-thirds weighed 

3,001-4,000 grams. Only a comparatively small 

proportion of births (2.1 percent) fell in the upper 

weight interval (4,501 grams or more). 

Race. -Nonwhite babies weighed on the average 

50 grams less than white babies (table C). Although 

this gap is small, there are some notable differences 

in the weight distributions of white and nonwhite births 

(figure 1A). 

A greater proportion of the nonwhite children 

were born at the immature weights and weights above 

4,500 grams, where the major problems of obstetric 

and pediatric care exist. Infants weighing 2,500 

grams or less represented 7.0 percent of all white 

live births as compared with 9.7 percent of nonwhite. 

At the highest weight level shown, the percent of nonwhite births (3.8) was double that of white (1.8). 

Comparison of the percentages of white and nonwhite births at weights around the modal groups for the 

distributions also reveals some variation. For both, 

the highest proportion of births occurred at 3,001-

3,500 grams. Around this peak, however, there was 

somewhat greater symmetry in the nonwhite distribution with the percentages of babies weighing 2,501-

3,000 and 3,501-4,000 grams being nearly equal. In 

contrast, the distribution of white births was weighted 

more heavily at 3,501-4,000 grams. 

Plurality= —Members of plural sets represented 

only 2.0 percent of all live births, but they accounted 

for 14.8 percent of the children weighing 2,500 grams 

or less at biiith. Figure lB indicates the extreme 

difference in the weight of children born in single 

and plural deliveries, which gives rise to this situation. In multiple deliveries, over half of the liveborn 

children (53.0 percent) were 2,500 grams or less at 

birth, while only 3.5 percent weighed over 3,500 

grams. This is in sharp contrast with the situation 

among single births, where the corresponding figures 

were 6.4 and 37.5 percent, respectively. 

In both single and plural births, the average weight 

was slightly lower for nonwhite children than for white. 

&.—Another characteristic shoting hportant 

weight differentials at birth is sex (figure lC). Fernak?s 

on the average weighed less than males. This was true 

in the case of both single and plural births in each 

race group. 

For single births in the white and nonwhite groups, 

there was very little difference in the proportions of 

male and female children weighing under 2,001 grams 

(table C). At 2,001-2,500 grams, however, the proportions of female births turned up more sharply, 

and the total group prematurely born according to the 

weight criterion was a fifth higher than that among 

males. 

The peak frequency class for both male and female births in the two race groups was 3,001-3,500 

grams. Comparison of the percentages on each side 

of this weight interval demonstrates, as do the average 

weights, the tendency of males, to reach, appreciably 

heavier weights in utero than females. A white male 

child was more than twice as likely to weigh 3,501-

4,000 as 2,501-3,000 grams. For females, the percentages in these weight groups nearly baIanced each 

other. A somewhat similar situation existed among 

nonwhite births. 

Larger proportions 

were found at the higher 

or’ nmre. For both male 

the proportion weighing 

ever, was higher than 

of male than female infants 

weights through 4,501 grams 

and female nonwhite infants, 

4,501 grams or more, howin either sex of white births. 

Gestation and birth wei~h 

Birth record information on length of gestation is 

seriously deficient. Some of the shortcomings are 

evident in the distributions of births by gestation 

shown in table D. 

The comparatively large proportions at 36 weeks 

of gestation result principally from the erroneous conversion of 9-month gestations to 36 weeks. Because of 

the distortion in the basic data, statistics for 36 weeks 

are shown separately. This type of error was also 

present at e6.rlier gestations although the broad inter-” 

vals into which the data are grouped reduce its effect. 

In addition, the heavy concentrations at 40 weeks tie 

indicative, in part, of a failure to calculate the period 

of gestation for infants who seem to be normally 

developed at birth. Although the main result of this 

is to lessen the numbers in the adj scent gestation 

intervals, some understatement of gestations of less 

than 36 weeks may also occur as a consequence. 

Because of the substantial errors, gestation age 

dsta can be taken as being only suggestive of what the 

actual situation might be. Figures are shown principally for broad comparative purposes, rather than for 

the absolute values. 

The percentage distributions of births by period 

of gestation in table D indicate that somewhat greater 

proportions of nonwhite than white babies were born 

before the 36th week of gestation. It is also clear that 

a much higher proportion of the plural than single 

births occurred relatively early in pregnancy. In the 

white group, 20.5 percent of the live births in plural 

sets occurred prior to the completion of 36 weeks of 

gestation, as compared with 3.1 percent for single 

births. The corresponding proportions among the, 

nonwhite were 17.6 percent for plural births and 3.8 

percent for single births. With regard to sex, however, there appeared to be little clifference in both 

the white and nonwhite groups in t@ proportions reported at these early gestations. 
Vol. 39, No. 1 WEIGHT AT BIRTH 11 

FIGURE 1 

BIRTH WEIGHT DISTRIBUTION OF LIVE BIRTHSI UNITED STATES, JANUARY I TO MARCH 31, 1950 

P,ERCENT IN lNtiViDUAL WEIGHT GROUPS CUMULATIVE PERCENT DISTRIBUTION 

Percent A-Race Percent A-Race 

100


80 1 

30 

60 

20


40


10


20 /


/ 0 ob~ 1,000 1,00 L [,501- 2,001- 2501- 3,00 L 3,50!- 4.001- 4.501 1,000 1,500 2,000 2,500 3,000 3,300 4000 4.500 TOILII or less 1300 2,000 2,500 3,000 3,500 4,000 4,500 07 mm? or less or k%, or less orI*5s or Iesz or leas or less or less 

B- Plurality B-Plurality 

100 

80 30
 / 

Plural 

60 /

/-7 20


/’ 40 /’

/’ 

20 /’ / 

.44 / 0 t ! ! , 

10 1,300 2,000 2,500 3,000 3,500 4,000 4,500 101 or less 1$00 2,000 2,500 3,000 3,500 4,000 4,500 or more 0 b orless orless or I es] ., 1,s. of less or less or less 

C-Sex C-Sex 40 100 

1,000 1,001. 1,501- 2,00! - 2,501- 3,001 - 3,501- 4,001. 4,501 1,( 

80
 30


60


/
 20 ,- —-
 f
 /
 40 — .-...-


10 k


20


0 I I I I 0


BIRTH WEIGHT (In worm) 
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12 VITAL STATISTICS—SPECIAL REPORTS 

TABLE D. PERCENTDISTRIBUTIONOF LIVE BIRTHS BY WEEKS OF GESTATION,RAOE, SEX, AND ETJJRALITY: 

UNITED STATES, JANUARY1 TO MAXCH 31, 1950 i 

(Birthstith gestationnot stated are distributed. Excludesbirths to resldentaof Maesaohusetlm
)

Under 37 Q 

BACEANDSKX Total 28 28-31 32-35 36 weeks 37-39 40 week8 

weeks weeks weeks weeks


100.0 0.6 

100.0 0.6 

100.0 0.6 

100.0 0.6 

100.0 0.6 

100.0 0.5 

100.0 0.8 

100.0 0. s 

100.0 0.8 

100.0 0.5 

100.0 0.5 

100.0 0.7 

and weeks weeks and


All racee 

M&le


Female


White


Male 

Female
 I


NonwMte


Male


over over


TOTAL BIRl?SS 

-

0.9 2.0 8.5 88.0 8.9 75.9 3.2
 -

0.9 2.1 8.4 87.9 

0.9 2.0 8.5 88.1 

0.8 2.0 7.8 88.8 9.3 76.1 3.5” 

0.9 2.1 7.8 88.7 

0.8 2.0 7.8 88.9 

1.3 2.1 12.5 83.3 6.9 7.4.9 1.5 

1.3 1.9 12.5 83.5 

1.3 2.2 12.5 83.~ 

—-


“ SINGLE BIRTHS 

I 

0.8 1.9 8.4 88.4 8.8 76.4 3.2


0.8 1.8 7.7 89.2 9.1 76.6 3.5


1.2 1.9 12.4 83.‘7 6.9 75.4 1*5


BIRTHS IN PLURAL SETS


5.2 10.8 12.7 67.3 14.9 51.4 1.1


5.3 11.4 12.3 67.2 16.1 50.0 1.2


4.8 8.2 14.6 67.9 9.3 58.0 0.6


Female


All racee


White


Nonwhite


AU races


White


Nonwhite


—


100.0 4.0 

100.0 3.9 

100.0 4.6 

NOTE.—Percent e for summarygroups ware independentlycomputedand thereforedo not necessarllyequal 

exactly the sum of the individualcomponentgroups.


In the broad. gestation intervals shown in table 

E, there is considerable dispersion of births by weight. 

Many children ivho would be considered premature 

according to gestation age weighed over 2,500 grams, 

and conversely many of the low-weight infants were 

reported as born at or near full term. For example, 

in about two-fifths of the single deliveries occurring 

in 32-35 weeks of gestation, the infants weighed over 

2,500 grams. Although the pl oportion of single births 

at gestations of 3? weeks and over that weighed 2,500 

grams or less was small (3.6 percent), this group 

represented half of the immature births. 

At all gestations, there were high proportions of 

births in plural deliveries weighing 2,500 grams or 

less at birth. Among those delivered before the 

completion of 36 weeks of gestation, all but a small 

segment weighed 2,500 grams or less. At the same 

time, lwo-fifths of those born at 37 weeks and over 

also fell in this weight group. In fact, half of the 

plural births immature according to the weight criterion were in this gestation group. 

Although a wide range of birth weights is represented in each gestation age group, the median 

weights by gestation follow a consistent pattern. 
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Vol. 39, No. 1 WEIGHT AT BIRTH 13 

TABLE E. PERCEWTDISTKIBUTIONOF LIVE BIRTHS BY B~TE WEIGET, WEE= OF GESTATION, RACE, AND PLUBALITY: 

UNITTEOSTATES, JANOABY 1 TO MARCH 31, 1950 

(Birthswith birth wei@ or gestationnot stated are distributed. Excludes births to resir3ents


of Massachusetts)


I WHITE I NONWE15 

1 t 

BISTS WEIGHT 37 I I 37 

(IN GRAMS)	 up 28-31 32-35 36 weeks U;$= 28-31


weeks weeks weeks weeks and weeks weeks


L 

All weights 100.0 1oo.o 

1,5,00or less 86.1 33.8


1,501-2,000 6.7 32.5


2,00L-2,500----------------------- 1.7 19.7


2,501-3,000------------7 1.5 5.9


3;001-3,500 -
 2.3 4.1


3,501 or more 1.7 3.9


2,500 or less 94.5 86.0


2,501 or more 5.5 14.0


over


SINGLE BIRTHS 

100.0 100.0 100.0 100.0 I 100.0 100.0 loo.o 10Q.O T

5.8 0.2 0.0 7~.8 34.6 7.1 0.3 0.1 

20.3 1.7 0.3 10.3 33.0 21.7 1.7 0.5 

33.6 8.9 3.0 2.4 20.4 33.9 8.4 4.7 

21.1 18.8 17.4 2.1 5.4 17.4 17.3 21.4 

12.7 34.4 40.0 2.3 3.5 12.9 31.2 37.6 

6.6 36.0 39.2 5.2 3.1 6.9 41.2 35.8 

59.6 10.8 3.4 90.4 88.0 62.8 10.3 5.2 

40.4 89.2 96.6 L9.6 12.0 T37.2 89.7 94.8

BIRTHS IN PLUBAL SETS


I I I I I ,1 

AU weight$--------------- 100.0 100.0 100.0 loo. o 100.0 loo. o 100.0 100.0 

* I I 

1,500 or less 93.1 55.4 14.2 3.3 1.2 90.6 47.2 16.3 4.8 2.6 

1,501-8,000 4.6 34.7 38.0 19.5 8.1 3.6 43.1 39.2 14.4 10.3 

2,001-2,500 0.9 8.2 33.9 41.3I29.5 4.3 6.3 30.6 35.9 30.9 

2,501-3,000 0.5 1.3 11.1 . 24.5 38.1 1.4 1.4 10.6 25.9 32.9 

$,oold3,500----------------------- 0.5 0.1 2.4 9.2 19.0 0 0 2.4 1.3.o 16.6 

3,501 or more 0.4 0.3 0.4 2.2 4.1 0 2.1 0.8 5.9 6.6 

2,500 or less 98.5 98.3 86.1 64.1 38.9 98.6 96.5 86.1 55.1 43.8 

2,501 or more 1.5 1.7 1.3.9 35-.9 61.1 II1.4 3.5 13.9 44.9 56.2

NO!E3 .—Percents for summsry GOups were independently.- cctsouted
and thereXoredo not necessarilyequal

exactly the sum of the individualcomponentgroups.


Among single birtbs, the medians for gestation groups 

below36 weeks all fdlat immature weights. For 

37 weeks and over, the figure is well above the immaturity weight level (table F). 

Male infants at each gestation interval weighed 

on the average somewhat more than fernale infants. 

In terms of gram differences, the excess was greatest 

at the mature gestation level. Relative to the average 

weight at each gestation, however, the gap betsveenthe 

weights of males and females was most pronounced in 

the very early group under 28 weeks. 

At gestation ages of 32 weeks or higher, the 

white children weighed slightly more at birth on the. f 

average than the nonwhite. A reverse relationship is , 

found at gestations under 28 weeks. The explanation 

for this may lie in reporting inaccuracies rather than 

in any developmental factor. Underreporting and 

misreporting as fetal deaths of the small infants who 

die soon after birth are believed to be more serious 

with respect to nonwhite births because of the high 

proportion not attended by physicians. 

7 
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14 VITAL STATISTICS-SPECIAL REPORTS 

TAME F. MEDIAN WEIGHTS OF LIVE BIRTHS BY WEEKS OF 

GESTATION,RACE,SEX,AND PLURALIIT:UNITEO STATES, 

JANUARY 1 TO MARCH 31, 1950 

(Birthswith birth weight or gestation not stated


are distributed. Excludesbirths to residentsof’


Massachusetts. Mediane computed to nearest 10


grams on basis of original reporting units of


pounds and ounces)


MEDIAN WEIGR’I!(IN GRAMS)


AT GESTATIONGROUP


RACE AND SEX
 37
 Under
 28-31 32-35 weeks


~::el weeks weeks and


over 

TOTAL BIRTES 

All races 92C 1, i’oc 2,310 3,350 

Male----------------- 940 1,720 2,340 3,410


Female 890 1,680 2,290 3,280


White 900 1,700 2,320 3,360


Ma~e 930 1,720 2,340 3>420


Female 880 1,680 2,290 3,290


Nonwhite 970 1,700 2,280 3,300


Male 970 1,730 2,290 3,350


Female 980 1,680 2,270 3,240


SINWE BISTHS 

All racea


White


Nonwhite
 m 

BIRTHS IN PLURAL SE?I!S


All races


tiite


:Nonwhite


m


lln~mput.iw we mdim weights for ~is gestation group, a further diviaionuaemadein the lowest


weight group shown in this report.


NEONATAL DEATHS 

Birth weighJ 

The risk of death among the newborn was closely 

related to the weight at birth. Among infants weighing 

2,500 grams or less at birth, the neonatal rate was 

173.7 per 1,000, compared with 7.8 among all other 

infants (table G). 

Only a very small proportion of’ We children 

weighing 1,000 grams or less lived through the first 

28 days. Chances of survival improvefl considerably 

with a moderate increase in weight, but a little over 

half of those weighing 1,001-1,500 grams also died. 

Mortality continued to decline steeply with each added 

500 grams of weight, and neonatal deaths in the highest 

group of the immature category (2,001-2,500 grams) 

amounted to 50.4 per 1,000 infants. Substantial decreases were recorded well into the mature, weights 

and the optimum birth weight group for the survival 

of infants fell at 3,501-4,000 grams. Additional weight, 

particularly when it brought the weight above 4,500 

grams, was on the average decidedly disadvantageous. 

Race. —The oyer-all neonatal mortality ,rate 

among nonwhite births was about 40 percent higher 

than that among the white. This excess was due, in 

part, to the ,differences in the weight distributions 

already described an~ in part, to substantially greater 

mortality among the nonwhite at weights above 2,500 

grams (figure 2A). If the wei@ distributicina for both 

white andmonwhite births were the same as the distribution for all births, the over-all rates would become 

19.6 for the white and 22.6 for the nonwhite. In 

standardizing rates in this manner, it is assumed that 

the differences between the birth weights of white 

and nonwhite infants are not of an intrinsic nature 

but reflect basically the effect of socio- economic 

and other demographic factors. Comparison of the 

standardized with the unstandardized rate clearly 

indicates the major reduction in neonatal mortality 

for the nonwhite group that would result froti bringing 

the weight distribution of nonwhite births closer to 

that for total births. 

At the lower wei@s, where the risk of mortality 

is great, nonwhite infants had a somewhat better 

chance of survival than the white. The mortality rates 

for the hvo groups differed only slightly at 2,001-2,500 

grams. However, in the higher weights at which a 

preponderance of the births occur, the mortality 

risk among nonwhite births was greater, with the 

gap between the two race groups becoming relatively 

wider at each successive level through 3,501-4,000 

grams and then narrowing slightly (figure 2A). 
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Vol. 39, No. 1 WEIGHT AT BIRTH 15 

TABLE G. NEONATALMORTALITY RATES BY BIRTH WEIGRT, RACE, SEX, AND PLURALITY:UNITED STATES, JANUARY 1 TO 

MARCH 31, 1950 

(Based on dedths within the first 28 days afterbirth among children born Jan. ltoMar. 31, 1950. Rates


per 1,000 live births. Births and deaths with birth weight not stated are distributed. Excludes data


for Massachusetts)


ALL RACES VJ31TE NONWHITE BIRTH WEIGHT 

(IN G=) 

~ =s ‘a’e‘em’e=s I ‘a’e‘em’e 

RATES AMONG TOTAL BIRTHS


All weightsl 20.0 22.7 17.1 18.9 21.6 16.0 26.7 29,4 23.9


—— 

1,000 or less 871.7 894.2 848.0 883.3 905.0 861.0 821.4 849.9 789.0 

1,001-1,500-------------- 551.3 621.8 478.2 562.1 643.1 474.5 507.0 524.7 491.6 

1,501-2,000 211.0 265.0 160.5 214.6 271.9 160.4 195.7 235.1 161.1 

2,00L2,500-------------- 50.4 67.4 36.6 50.6 69.1 35.5 49.5 60.0 41.2 

1,000 or less 871.7 895.1 846.7 880.2 903.8 855.2 835.2 858.5 809.0


1,001-1,500-------------- 562.3 629.1 489.6 575.0 648.5 489.9 511.0 537.4 488.8


1,501-2,000 228.9 281.1 178.3 238.4 294.5 182.2 190.0 221.3 163.1


2,00L2,500-------------- 52.8 71.1 38.3 53.5 73.2 37.7 50.0 62.1 40.6


2>501-3,000-------------- 12.6 16.7 9.5 12.2 16.1 9.2 15.1 19.7 11.3


3,001-3,500-------------- 6.7 8.1 5.3 6.2 7.6 4.9 9.5 10.7 8.4


3,501-4,000-------------- 5.6 6.4 4.6 4.9 5.6 4.0 10.4 12.1 8.4


4,001-4,5W 7.4 7.6 7.2 6.7 6.8 6.5 12.3 1.3.o 11.2


4,501 or more 14.2 13.7 L5.1 12.1 10.8 14.7 20.3 23.2 16.0


2,500 or less 173..4 215.6 137.1 176.7 222.1 137.1 1.59.5 167.2 135’.o


2,501 or more------------ 7.7 9.0 6.3 7.1 8.3 5.8 11.7 13.7 9.6


2&01-3,000-------------- 12.6 16.6 9.5 12.0 15.9 9.1 15.4 19.9 11.8 

3,001-3>500-------------- 6.7 8.1 5.3 6.2 7.6 4.9 9.7 10.9 8.4 

3,501-4,000 5.6 6.4 4.6 4.9 5.6 4.1 10.5 12.2 8.4 

4,00L4,500-------------- 7.5 7.7 7.2 6.7 6.9 6.4 12.5 13.1 lL4 

4,501 or more------------ 14.2 13.7 15.1 12.0 10.8 14.7 20.2 23.1 16.0 

2,500 or less 173.7 213.9 138.9 175.8 218.8 138.4 164.7 192.8 141.3 

2,501 or more------------ 7.8 9.1 6.4 7.1 .9.3 5.8 11.9 13.9 9.7 

RATES AMONG SIItG13BIRTHS 

‘T All weights 18.3 20.9 15.6 17.3 20.0 14.5 24.4 26.9 21.8 

All weights 98.6 I 

I 107.9 

1 

88.9 

RATES II AMONG 

94.4 

BIRTHS 

11

103.6 

INPLUFW 

f

T

85.2 

SETS


I 

118.0 

Ii


r

3.28.2 107.1 

1,000 or less 871.5 890.2 853.4 898.0 910.8 886.2 7s4.0 808.8 689.7 

1,001-1,500-------------- 503.7 585.8 434.1 507.1 615.6 418.8 409.0 472.5 505.5 

1,501-2,000-------------- 145.4 200.4 100.8 129.5 179.3 90.6 218.4 287.7 1.52.5 

2,001-2,5C0-------------- 32.9. 43.1 23.3 30.2 42.7 18.4 45.6 245.0 46.2 

2>501-3>000-------------- 11.3 13.7 8.6 8.5 11.8 24.9 25.8 223.9 227.8 

3,001-3,500-------------- 10.4 ‘%0.7 29.8 28.0 26.9 29.4 222.4 229.5 %2.1 

3,50L4,000--------------

4,001-4,500--------------

4,501 or more 

218.7 =13.3 

238.1 (3) 

(3) (3) 

227.8 

(3) 

(3) I 

%6.6 

(3) 

r’) 

28.8 

r) 

(3) 

230.1 

r) 

(=) , 

225.0 

(=) 

(s) r 

f~ 

(:.) 

[9] 

2,500 or less 

2,501 or more------------

175.6 I 204.4 

11.8 13.2 

149.7 

10.0 

171.0 

9.0 

199.9 

10.5 

145.3 

7.2 

196.9 

25.3 

224.5 

26.6 

170.5 

23.8 

.— lIn~l~di~ data for Massachusetts,the over-all rates become: All races} 19.9; white, 18.8; nonwhite, 

26.6.


2This rateis sub$ectto wide variability. It is basedonmore than 100 birthsj but less than20 dea~.


?Rate not computed for this group because of small numbers of births (less than 100] and deaths (1.eso


than 20) occurring in the interval.

16 VITAL STATISTICS-SPECIAL REPORTS 

FIGURE 2 

NEONATAL MORTALITY RATES BY BIRTH WEIGHT, 

UNITED STATES, JANUARY I TO MARCH 31, 1950 

(Rates per 1,000 live births) 

Rote A-Race 

1,000 

600 

400 

200 

lca 

60 

\ 40 

20 

Wti te 10 — —-

6 

! 1 , 1 I I 1 

lb 1,001. 1,501- 2,001 - 2*01- 3JKl~ 4,001- 4,501 

or less (,500 2,000 2,500 3,CC.J &% 4,500 ., mm 

B-Plurality 

!,000


200 

I00 

.~ 

1,000 1,001- 1,50!. 2,001- 2,501- 3pol. 4,501 

.x 1,, s 1,500 2,000 2,500 3,000 3,500 4:000 4:500 or mm 

‘“t------’\-\ I 

BIRTH WEIGHT (in grams) 

NoTE. Weight scale may be viewed as being continuous with the fOteS 

plotted at midpoints of the weight intervols. 

For both white and nonwhite babies, the risk of 

mortality was reduced markedly with increasing 

weight until well past the prematurity level. The 

sharpest relative reductions in mortality in each race 

group, however, occurred at weight intervals 2,001-

2,500 and 2,501-3,000 grams. At these levels the 

addition of 500 grams meant cutting mortality by twothirds to three-fourths. 

Among white children, the group weighing 3,501-

4,000 grams had the lowest mortality. The neonatal 

rate at this optimum level, 4.9 per 1,000 was only a 

fourth the figure for all weights, 18.9. For the nonwhite races, children weighing somewhat less (3,001-

3,500 grams) experienced the lowest mortality. While 

the rate for this optimum group (9.7) did not compare 

quite as favorably with the over-all rate as in the case 

of white births, it was also far below the neonatal ‘ 

rate for all weights combined (26.7). 

Plurali~-Because of the heavy preponderance 

of plural births at the low weights, the neonatal mortality rate for babies born in multiple sets was five to 

six times the rate for single births. On a weight-specific basis, the mortality risk among plural births 

was actually lower than among single births between 

1,001 and 3,000 grams. Above this point, however, 

single births had a major advantage (figure 2B). 

The relationships observed between rates in the’ 

case of total births also hold for single events for 

the white and nonwhite groups. For plural births, 

however, the situation was not at all the same. White 

children at all weights above 1,500 grams experienced 

lower mortality than the nonwhite at comparable 

weights. The differential was most marked between 

2,501 and 3,500 grams, where the mortali~ risk among 

the white was about a third of the nonwhite. 

&.-During the neonatal peribd, the mortality 

risk for males and females differed greatly at almost 

every weight level, and the over-all mortality rat e 

among females was only three-quarters of that among 

males. 

The prognosis was considerably better for girls 

thsn for boys at most weights in both the white and 

nonwhite groups (figure 2C ). In the white. race, the 

neonatal mortality rates for females at weights behveen 1,501 and 3,500 grams were one-half to twothirds of the rates for males. Only in the highest 

weight group (4,501 grams or more) was the rate 

lower for males. Sex differences in mortality in the 

nonwhite races were %lightly less pronounced than in 

the white at most premature weight levels and also 

at weights between 2,501 and 3,500 grams. h the 

weight group 4,501 grams or more, the rate for the 

nonwhite female was less than that for the male. 

Table G gives mortality rates for both single 

and plural births by race and sex as welLas rates 

for the two groups combined. Compariso~ based on 

single births do not change the relationships already 

discussed. It will also be noted that for this group 

race differentials among males weighing betxveen 

1,001 and 2,500 grams were larger than those among 
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Vol. 39,. No. 1 WEIGHT AT BIRTH 17 

females. In fact, for single immature births, as a 

group, there was no difftience bel?weenwhite and nonwhite female mortality, but the rate among white 

males was 19 percent above that for nonwhite males. 

Tnthe weights above 2,500 grams, race differences for 

each sex were large, with the white groups having the 

hwer rates. 

By treatfng the mortality experience of males 

and females in the same weight cla.i%as comparable, 

no account is taken of developmental differences that 

may exist. An evaluation of these differences is 

needed, but will require more detailed data than are 

amilable from the present study. In this comection, 

it is of interest, however, to compare the weight levels 

at which male and female mortality correspond. For 

this purpose, the mortality rates per 1,000 live births 

for sfngle white males and females by 250 gram inter-’ 

tis are shown below. These rates indicate that at 

many points in the range 1,001 to 3,000 grams (the 

highest weight for which data in this detafl sre avail5ble) males had to weigh about 250 grams more than 

females to have Somewhat the same chance of 

Survfval. 

W~igll	 —— 

Male Female

1,001-1,250 $jTSInS-------- 731.7 589.3 

1,251-1,500 grams 579.4 412.3 

1,501-1,750 glW.XIS--------383.0 246.0 

1,751-2,000 g’I’S.mS 246.0 147.7 

2,001-2,250 grams il’7.l 59.5 

2,251-2,500 grams 55.8 30.2 

2,501-2,750 gIYWkS 23.8 13.2 

2,751-3,000 gl%illlS--------11.6 6.8 

There fs evidence, however, of a basic differential 

in mortality Liehveenthe sexes that ts not taken care 

of by this approach. This arises from the fact that 

at no point fn the weight scale does mortality for 

males reach the low recorded for females. 

Gestation 

Inadequate as we gestation data are for exact 

measurements, they do demonstrate the sharp changes 

in the mortality risk with increasing gestatton age. 

About l“out of eyerj 3 infahts born at 28-31 weeks of 

gestation died in the neonatal period, as compsrqi with 

1 in 8 at 32-35 weeks, and less than 1,tn 100 at 37 

weeks and over (table H). 

At gestations through 35 weeks, mortality was 

about 10 percent lower among nonwhite than among 

white children in single births. For infants born 

after the completion of 37 weeks of gestation, however, neonatal mortality was about two-thirds htgher 

for nonwhite siingle births than for white. h-plural 

births, the experience among the nonwhttes was better 

only in the gestation group under 28 weeks. Major 

differentials in relative loss were also found between 

the sexes at each cf the broad gestation levels given. 

788-637
O-65—3


TABLE H. NEONATAL MORWUZL’YRATES BY WEEKB OF GESTATION,IWE, SEX, AND PmRAU!m Uml!EO STATES, 

JANUARY 1 TO MARCH 31, 1950 

(Basedondeaths withinthe first 28 days after birth


-W childrenborn Jan.llm M. 31, 1.850.Rates


per 1,000 liva births. Births aud deaths with


gastationnot stated are disbrilwtecl.Excluaes


data for Massachusetts)


RATES AMONG TOTAL BIRTHS 

I I 1 I 

All races-- 788.4 379.4 121.3 18.4 8.8 

Male 811.9 419.6 140.3 22.2’ 10.1 

Female--------- 76L4 334.0 101.0 14.4 7.5 

White-----=-- 803.6 387.9 122.4 18.1 8.1


Male 825.9 429.5 142.1 22.4 9,.2


Female--------- 777.6 339.1 100.5 13.5 6.8


Nonwhite 724.4 346.5 115.4 19.7 X5.8


Male----------- 21.5 15.9


Female 17.8 11.7 -


RATES AMOIiG SINGIZ BISTHS 

I I I I 

All races-- 779.1 365.4 118.0 17.2 8.6 

White 793.5 374.3 119.7 17.1 7:9


Nonwhite 718.3 332.4 108.9 17.9 13.1


RATES AMONGBIRTHS IN PLURAL SX!l!S 

I I I I


All races-- S47.2 484.8 148.4 55.1 24.5 

White 868.9 484.6 144.3 48.9 19.1


Nonwhite - 760.9 486.1 175.5 80.1 49.6


Female infants experienced considerably lower 

nmrtality than dfd the male in all groups. 

Gestation and bfrth weigh~ 

/’ 

Mortality varied greatly by weight within each 

gestation group and by gestation wfthfn each weight ‘ 

group. At each gestation level, mortality dropped off 

sharply as .weigbt increasec$ and reached a low pofnt 

at the more +ture weights. Sfmdlarly, among children fallfng in the same weight group, the mortality 
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18 VITAL STATISTICS-SPECIAL REPORTS 

rate declined as the gestation age approached term~ 

For an intensive study of the separate and joint influence of gestation age and birth weight, it would be 

necessary to use smaller intervals for both of these 

characteristics than was warranted by the information 

available for this report. Despite this shortcoming, 

the data in table I give come indication of the important 

effect that both gestation and birth weight have on the 

survival of the newborn. For example, the loss during 

the neonatal period among white babies weighing 

TABLE I. NEONATALMQRTALITYBATES BY BIRTS WEIOHT, 

- OF GESTATION,ANO RACE: UNITZYlSTATES, JANUARY 1 TO MARCH 31, 1950 

(Basedon deaths withintl.w
first 2S days after birth 

amons childrenborn Jan.1b Mar. 31, 1950. Rates 

per 1,000 live births. Births and deaths with 

birth weight or gestationnot stated are distributed. lIkcludesdata for Massachusetts) 

37 RACE AND Under 28-31 32-35 36 weeks BIRTH WEIGHT 2s weeks weeks weeks and (IN omfs) weeks over 

WHITE


1,000 or less- 914.7 828.8 787.0 1428.6 485.3 

1,oo1-1,500--- 762.2 560.0 416.6 377.5 353.1 

1,501-2,000 593.9 345.8 204.8 142.6 119.5 

2,001-2,500--- 400.0 187.6 92.7 49.9 33.5 

2,501-3,000 (2) 108.4 51.3 18.1 10.1 

3,001-3,500 (2) 136.5 23.Q 8.3 5.9 

3,501-4,0co--- (:) ’48.0 111.3 6.1 4.8 

4,00 L4,500--- (2) 190.5 9.6 5.9 

4,501 or niore- H (2) (2) %.3.9 11.5 

NONWHITE


1,000 or lea6- 865.9 800.0 766.7 1500.0 ~419.4 

1,oo1-1,500--- 743.3 467.8 383.7 1383.0 347.5 

1,501-2,000 566.7 284.9 155.7 143..4 134.9 

2,00 L2,500--- (2) 190.6 S6.1 54.9 32.9 

2,50L3,000--- (2) (2) 144.9 1.3.3 14.4 

3,001-3,500--- (2) (2) 126.8 11.3 9.2 

3,501-4,000--- (2) ~:] 140.0 9,4 10.4 

4,001-4,500 (2) (2) ~lo.1 11.9 

4,501 or more- (2) (2) (2) 116.3 20.7 

%This rate is subjectto wide variability. It


is based on more than 100 births, but less than 20


deaths.


%ate not computedforthis group becauseof small


numbers of birtha (less than 100) and deaths (less


than 20) occurringin the interval.


3SUpDlementarYdata not shown here ~dicate an 

upturn in mortality as gestationage extended much


beyond term. 

3,001-3,500 grams and born at gestations of 32-35 

weeks, was considerably smaller than that among 

tnfants weighing between 2,001 and 2,500 grams and 

born after the completion of at least 37 weeks of 

gestation, but it greatly exceeded the rate for those 

weighing 2,501-3,000 grams who were born at or near 

term. Similar relations, emphasizing the need,to 

consider both gestation and birth weight in evaluating 

mortality experience, may be noted in the data for 

nonwhite births. 

The differences bebueen the rates for males and 

females according to birth weight within a gestation 

group (table J) were generally greater than in the” 

gestation group as a whole (especially among white 

births). This apparent contradiction can be explained 

by the previously discussed differences ‘m the weight 

distributions of male and female births within each 

geststion group. It is worth noting that the rate among 

males in the optimum weight-gestation class was 

above the minimum recorded for females. The same 

situation held when more detailed data than shown in 

table J were examined. Thus, it would appear that 

an explanation of the sex, differential in mortaliw, at 

least among the more favorable risk groups, would 

have to be sought among factors other than weight 

or gestation. 

ATTENDANT AT BIRTH 

The discussion in this section distinguishes 

between births that occurred in hospitals and those 

that were delivered at home4 either by a physician 

or nonmedical person. While both race groups shared 

in the marked increase in the use of hospital facilities 

that took place during the 1940-50 decade, almost 45 

percent of the nonwhite births in Janusry-kfarch 1950 

were delivered at home (table 4). A substantial proportion of these were to rural residents in the Sout!I 

with midwives as the attendants. In the white race 

8 percent of the births occurred out of ahospital, 

with a large fraction of these having a physician in 

attendance. 

In interpreting the relationships presented below, 

it should be borne in mind that the attendant data do 

not take into account subsequent hospitalization of 

some of the infants delivered at home or the medical 

care received by others soon after delivery by a 

nonphysician. The effect of these factors could be 

appreciable in communities where special programs 

for the care of prematurely born tnfants existed. 

A more significant factor for “attendant” statistics is the possible selection of obstetrical cases 

presenting complications for referral to hospitals, 

where ordinarily the mother would have remained at 

4The phrase ‘ ‘at home ‘ ‘ refers to all deliveries 

occurring out of hospitals or Institution. 
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Vol. 39, No. 1 WEIGHT AT BIRTH 19 

TABLE J. NEONATALMORTALITYRAT!ESBY BIR5 WEIGET, WEEKS OF GESTATION,RACE, ANO SEX: UNITED STATES, 

JANUARY 1 ‘TOMARCH 31, 1950 

(Basedon deathswithin the first 28 days after birth among childrenborn Jan. 1 to Mar. 31, 1950. Rates


per 1,000 live births. Births and deaths with birth weight or gestationnot stated are distributed.


Excludes data for Massachusetts
)


I 

w .. 

I I I FACE W BIRTH WEIGET 37 37 (IN GRAMS) Under 28-31 32-35 weeks Under 28-31 32-35 weeks
 28 28
 weeks weeks and weeks weeks end
 weeks weeks
 over over


White -1- 825.9 429.5
 142.1 9.2 777.6 339.1 100.5 6.8 

1,500 or less 8s5.7 699.4 517.3 449.4 S44.1 556.7 403.9 326.1 

1,501-2,000 

2,001-2,500 

640.2 

(1) 

389.4 

214.4 

251.7 

115.7 

161.8 

45.9 

51.5.5 

(1) 

294.2 

150.3 

1.58.3 

66.9 

87.4 

24.7 

2,50L3,000---------------------

3,001-3,500 

3,501 or more 

(1) 

(1) (.1) 

1.38.6 

263.1 

276.9 

63.3 

29.7 

232.4 

13. o 

7.2 

5.9 

(1) 

(1) 

(1) 

276.4 

29.3 

(=) 

37.1 

216.2 

233.0 

8.0 

4.7 

4.6 

Nonwhite 3.28.7 1.5.9 695.0 316.1 103.5 11.7 

I 

1,500 or less 860.8 617.4 421.1 342.9 785.5 508.5 457.9 379.7 

1,501-2,000 600.0 288.5 211.9 162.B 533.3 281.5 108.7 13.2.0 

2,001-2,500 (1) 242.0 77.7 43.5 (1, 2133.8 93.5 25.1 

2,501-3,000 252.1 18.5I

(1)(1)=’39 .0 Il..o


3,001-3>500--------------------- 246.4 10.4 (=) [:; =6.8 8.1


3,501 or more (=) X5.3 (=) (=) 9.8
 I I I 

+/ate n~ ~mputed for &iE group because Of small numbers of births (less ~~ 100) ~ dea~ fless 

. than 20) occurri~ in the inter%il.-
 2mia rate is subJect to wide variability. Itisbasedm more than 100 births,but less than 20 deatis.


home for the delivw, also, the calling in of physicians 

by come midwives to handle difficult deliveries. In the 

nonwhite group, where midwives had a critical role, 

this selectivity may have been a particularly importit factor. Duing the 1940’s, tie Underst=ding of 

the midwife about the need for medical intervention 

in certain cases had increased greatly as a result of 

contacts by public health nurses snd their success in 

having midwives bring patients to prenatal clinics. 

Several qualitative factors also enter into the 

consideration of birth weight statistics for the various 

attendantcategories. ‘f’he most accurate infor=tion 

is unquestionably obtained for the births occurring 

in hospitals. Many of the attendants who weighed 

infants born at home used fairly crude scales, calibrated by quarter pounds. In addition, whether or not 

a &kiwife, for example, made a correct allowance for 

the diaper, blanket, or other material in which the 

newborninfantwas wrw would have an appreciable 

effect on thebirth weight distribution. 

Still another factor that may be qn?rating differentially smong births at home and in the hospital, is 

underreporting 01 infantswho die shortly after birth 

or misreporting them as fetal deaths. Although no 

objective measures are available, tie general level 

of registration completeness alone, which is greatly 

in favor of the latter group, would make it reasonable 

to assume that this biasing situation is far more apt to 

occur auwng births at home. 

These qualifications tmpose heavy restrictions 

on the inferences that can be drawn from current 

statistics on deliveries occurring out of hospitals. 

However, a number of the relationships found are 

highly suggestive and could be used as the framework 

for more intensive investigations. 

Weight — distribution and neonatal mortality

Babies born in hospitals generally weighed less 

at birth than those delivered at home. Tnfantsdelivered 

by nonphysicians were on the average the heaviest, 

weighing about 140 grams more thsn the babies ‘delivered by physicians at home and 260 grams more 

than the hospital births (table K). 
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20 VITAL STATISTICS-SPECIAL REPORTS 

TAPLE K. PERCENTDISTR~ION OF LIVE BIRTHS AND NEONATALMORTALITYBATES, BY BIRTH WEIGRT,RACE, 

AND A!M!ENDANPAT BIRTH: UNI!CEOSTATES,JANUARY 1 TO MARCH 31, 1950


(Neonatalmortalityratee based on deathswithin the first 28 days after birth among childrenborn Jan. L


to Mar. 31, 1950. Rates per 1,000 live births. Birthsand deathswith birth weight not stated are,dis.


tributed. Excludes data for Massachusetts
)

ALL RACES II WHI’I!E I NONWHITE 

BIRTH WEIGHT 1

Physi- Physi- Midwife, Physi- Physi- Midwife, Physi- Physi- Midwife,


(IN GRAMS) cIan cian other, cIan cian other, cian Cian other,


in not in and not in not in and not in not in and not


hos­
 hos- speci- hoa- hos- speci- hos- hos- speci­


pitall pital fied pital~ pital fied pitall pital fied


1


PERCENTDISIRmUTION OF B~TELS2


All weights 100. c 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0. 

1,000 or less o.~ 0.5 0.3 0.4 0.5 0.4 0.9 0.5 0.2 

l,ooi-l,500 ---”- 0.6 0.7 0.5 0.6 0.6 0.8 1.0 1,1 0.4 

1,501-2,000 1.4 1.2 1.2 1.3 1,1 1.4 2.2 1.6 1.2 

2,001-2,500 5.0 4..5 4.4 4.7 4.0 4.9 7.8 5.7 4.2 

2,501-3,000-------------- 18.8 14.8 12.0 18.1 X5.3 12.1 25.8 18.7 12.0 

3,001-3,500 38.7 33.7 28.0 58.6 33.3 28.0 39.0 34.9 28:0 

3,501-4,000 26.6 29.1 31.6 27.4 30.2 31.1 18.3 26.3 31.7 

4,W14,500-------------- 7.1 10.6 1.3.1 7.4 11.7 13.o 4.0 7.6 1.3.1 

4,501 or more 1.4 4.9 8.9 1.4 5.3 8.4 1.0 3.7 9,1 

2,500 or lesa 7.5 6.9 6.4 7.0 6.2 7.4 11.9 8.8 6.1 

2,501 or more 92.5 93.1 93.6 93.0 93.8 92.6 88.1 91.2 93..9 

Median weight (in grems)g 3,300 3,420 3,560 3,320 3,460 3,540 3,150 3,320 3,560 

KSONATAL MCIRTALITY RATES 

I I 

All weights 19.1 25.6 26.4 18.2 23.7 35.9 27.4 30.6 23.6 

1 1 1 1

1,000 or leas 882.4 793.0 766.7 890.8 796.5 833.3 839.4 784.1 730.8 

1,001-1,500 549.5 556.7 572.0 558.1 577.3 677.8 500.8 524.3 51.2.5 

1,501-2,000 203.7 265.2 263.1 211.5 255.6 246.7 158.5 283.6 268.9 

2,001-2,500 45.7 78.9 91.7 46.7 94.6 115.7 39.8 48.7 63.2 

I I


2,501-3,000 11.2 23.5 27.4 11.2 22.4 35.2 11.2 25.6 24.7 

32001-3,500 6.0 10.9 14.9 5.8 10.5 21.5 7.8 12.1 12.9 

3,501-4,000 5.0 7.1 11.5 4.7 5.7 12.6 9.5 11.7 11.2 

4,001-4,500 6.7 6.7 1.3.O 6.3 7.5 16.8 13.0 13.6 11.8 

4,501 or more 1.3.o 15.3 16.4 10.8 13.7 20.5 44,1 21.5 1.5.2 

2,500 or leas 169.5 211.6 191.3 171.6 223.6 238.4 157.5 188.5 173.7


2,501 or more 6.9 11.7 15.2 6.7 10.5 19.7 9.8 15.2 X5.9


lit ~~ assaed t~t all bi~~ in hospitalsor i~titutio~ .re attendedby physicianS.


2Percentsfor aUISWWY =OUPS were independentlycomputedand thereforedo not necessarily. equal .
 exactly


the sum of the indlviduil-c~onent groupe.


‘Computedto nearest 10 grams on basis of originalreporti?ig
units of pounds and ounces.

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Vol. 39, No. 1 WEIGHT AT BIRTH 21 

The divergence in the weight distribution among 

white births did not become large until the upper 

level of immaturity (2,500 grams) was passed. But 

important differences from one attendant group to the 

other were observed starting with the lowest weight 

group for nonwhite births. Here the proportion of 

hospital births weighing 2,500 grams or less (11.9) 

was almost twice the figure for midwife deliveries 

(6.1). 

Although some of the biases mentioned previously 

could have produced the cliffer ence in incidence of 

immaturity noted for the nonwhite birtbs, it is unlikely 

that they could account for the entire amount. A full 

explanation would have to cover such things as birth 

order of the children involved, and the distribution of 

fetal loss from the earliest stage of pregnancy. 

At the other end of the birth weight scale, i. e., 

in the group weighing 4,501 grams or more, was 

concentrated a substantial proportion of both the white 

and nonwhite infants delivered by midwives. These 

cases were relatively less frequent among the deliveries taken care of by physicians at home, and 

formed a very smali percentage of the hospitai births. 

A@@ the magnitude of the vsrisbiiity suggests that it 

is not entirely due to “artificial” factors but that other 

causes must be sought. 

The record of survival among white births was 

greatly in favor of hospital events. The advantage 

over the nomnedically +tended births was especially 

marked in weight groups above 2,000 grams. In each 

of these weight intervals, the mortality rate among 

infants delivered by nomnedical persons was tio to 

four times that found among hospital deliveries. The 

ex&rience in the group handled by physicians at home 

fell between that in hospitals and that of midwives in 

most weight intervals. 

In the nonwhite races, the neonatai mortality rate 

for all of the midwife deliveries was lower than the 

rates for deliveries in the other two attendant categories. The higher rate for hospital births is not 

entirely unexpected, in view of the relatively small 

proportion of midwife deliveries that fell at the low 

weights where the mortality risk was highest. 

Actually, in the weights between 2,001 and 3,000 

grams, within which the mortality rate declined 

precipitously, the neonatai loss among nonwhite babies 

delivered by midwives was twice that among the events 

in hospitals. It was only at weights above 4,500 grams 

that hospital births had a much higher rate. Births 

attended by physicians at home had a lower mortality 

rate than the nomriedically attended only in the weight 

gi’OUpS 2,001-2,500 and 3,001-3,500 grams. 

Considering the weight specific rates, it is not 

surprising that among nonwhite births the over-all 

neonstsl mortaiity rate standardized for weight is ,far 

more favorable for hospital births than for either of 

the other two categories.5 A comparison of standardized and unstandardized rates for the nonwhite birtis 

by attendant foiiows: 

Attendant Standardized Unstandardized 

Physician in 

hospital 24.6 27.4 

Physicisa not 

in hospital 31.5 30.6 

Midwife, other, and 

not specified 32.7 23.6 

One of the interesting features of the weight 

specific rates among nonwhite births that occurred in 

hospitals was the exceptionally sharp increase as the 

babies’ weights entered the interval 4,501 grams or 

more. The rate for infants weighing this much (44.1) 

was even above the level for the weight interval 2,001-

2,500 grams. Furthermore, the figure was much 

higher than the comparable rate in any other attendant 

group handling either white or nonwhite deliveries. 

This situation more than any other relationship 

revealed by the data suggests a selectivity of difficult 

cases by both midwives and physicians for referral to 

,hospitals. There is a distinct possibility that a sufficiently large number of attendants called for hospital 

aid when faced with difficulties in the delivery of the 

very large babies to affect seriously the rate for nonwhite hospitai births at this weight. The differences 

between doctors and midwives, in rates among homedeliveries, might also refiect the operation of a selectivity factor in favor of the midwife group. 

Within each race, about the same proportion of 

the births delivered at home and in a hospital were 

members of plural sets. The advantage, previously 

discussxi, that went with hospitalization at time of 

birth held for both the single and the plural birth 

groups (table L). In view of the special problems that 

arise in the delivery of multiple births and in their 

care @er parturition, Mspi-on woulcl be expected 

to be a more important factor for these births than 

for single births. This is borne out by the experience 

in several of the weight groups-especially, among the 

nonwhite babies weighing 2,501 grams or more. However, the+attern was not consistent throughout the 

weight range. 

5For the white race there was virtually nd 

difference between the standardized and unstandardized rates. 
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22 VITAL STATISTICS—SPECIAL REPORTS 

TABLE L. NEONATALMORTALIti RATES AMONG BIRTHS IN 

HOSPITAISAND NOT IN HOSPITAIS, BY BIRTH WEIGHT, 

RACE, AND PLURALITY:UNITED STATES, JANUARY 1 90 

MARCR 31, 1950 

(Basedon deathswithinthefirst 28 days after birth


among childrenborn Jan.1to Mar. 31, 1950. Rates


per 1,000 live births. Births and deaths with


birth weight not statedaredistributed. Excludes


data for Massachusetts
)


WHITE NONWRITE


BIRTE WEIG6T


(IN GRAMS) In Not in In Not In


hos- hos- hos- hos­


pital pital pital pital


AMONG S NGLE BII !Rs 

1,000 or less-- 887.7 796.3 853.2 772.1 

1,oo1-1,500---- 571.3 610.2 510.1 512.8 

1,501-2,000 235.9 269.S 154.2 271.5 

2,001-2,500 49.3 106.4 40.9 69.1 

2,500 or less-- 172.3 229.9 153.7 172,1


2,501 or more-- 6.6 12.1 9.8 14.0


RATES AMONG BIR!I!SS
 IN PLURAL SETS


1,000 or less-- 905.3 e26.9 770.8 700.0 

1,oo1-1,500---- 502.1 558.8 454.5 541.7 

1,501-2,000 124.5 194.4 177.8 2s4.s 

2,001-2,500 27.9 130.5 72.1 

2,500 or less-- 167.5 210.2 le2.8 221.8 

2,501 or more-- 8.2 116.5 110.1

155.1 L40.s 

%his rate is sub~ectto wide variability. It


is based on more than LOO births,but less than 20


deaths.


SINGLE BIRTHS IN HOSPITALS 

The birth weights considered thus far have been 

principally in 500 gram intervals, or slightly more 

than 1 pound. This was selected as the measuring unit 

to reduce the effect on comparisons of the errors 

associated with the weight information for births 

that occurred at home. Class intervals of 250 grams 

for single births in hospitals are introduced in this 

section for the weight range between 1,001 and 3,000 

grams to discern more clearly the points atwhich 

marked changes in the rate of decline in mortality occur. 

While it would undoubtedly be desirable to measure 

in finer intervals, lack of control and specific knowledge about the errors that exist even in hospital data 

would make this highly questionable. Also, many of the 

frequencies would be too low for close study. 

In emmining mortality differences between white 

and nonwhite births that are delivered in hospitals, it 

should be kept in mind that the data are for all hospitals combined. The heterogeneity among hospitals 

in types of services availshle for handling prematurely 

born infants is probably reflected differentially in the 

figures for white and nonwhite hospital births. 

The mortality data by race for single births in 

hospitals, shown in table M and figure 3, clearly indicate. the significance of relatively small increases 

in weight on the mortality rate. Among white babies, 

the addition of 250 grams to the birth weight of an in-. 

fant meant a large reduction in the mortality risk. 

From one 250 gram group to the next, over the range 

of weights between 1,751 and 3,000 grams? the mortality rate was cut approximately in half. It is” particularly noteworthy that at this stage of development 

in the special efforts to save the immature infant, the 

rate of decline in the neomtal loss was about the same 

over an interval which ticludes both prematurely born 

and mature babies. In the lower weights, percentage 

reductions were important ~t not as large. 

A slowing down in the rapid rate of decline in 

mortality occurred when the weight group 3,001-3,500 

grams was reached. As in the case for all births 

combined, the optimum weight interval among single 

white births in hospitals was 3,501-4,000 grams. 

The downward sweep in the nonwhite mortality 

rate as ‘birth weight increased had a number of points 

r~~ M. NEONATAL MORTALITY RATES AMONG SINGLE


BIRTHS IN HOSPITALS,BY DETAILEDBIRTH WEIGHT AND


RACE: UNXCED STATES,JANUARY 1 5?0MARCH 31, 1950 “


(Basedon deathswithinthe first 28 days after birth


emong childrenborn J&m.1to Mar. 31, 1950. Ratea


per i,000 live births. Births and deaths with


birth weightnot stated are distributed. Excludes


data for Massachusetts
)

BIRTH WEIGET All Non-
 White
 (IN GW) races white


All weights


1,000 or less 

1,001-1,250 

l/251-l jam-----------

1,501-1,750


1,751-2,000


2,001-2,250


2,251-2,500


2,501-2,750 

2,751-3,030 

3,001-3,500 

3,501-4,000 

4,001-4,500 

4,501 or more---------

17.5 16.7 25.1


882.0 e87.7 853.2 

660.2 668.1 614.4 

480.1 489.5 430.9 

297.6 315.4 203.1 

181.6 191.6 3-25.5 

81.9 84.2 67.4 

35.5 36.0 32.4 

16.2 16.6 13.8 

8.4 8.3 9.5 

6.0 5.8 7.8 

5.0 4.7 9.5 

6.6 6.3 ‘12.7 

1.3.O 10.8 44.1 
Vol. 39, No. 1 WEIGHT AT BIRTH. 23 

-.. 

NEONATAL MORTALITY RATES AMONG SINGLE BIRTHS Ihi HOSPITALS, BY DETAILED BIRTH WEIGHT AND RACE: 

UNITED STATES, JANUARY I TO MARCH 31, 1950 

1,000 

800 

600 — 

400 

\\ 

~ 200 

I 

+ 

g 

m Nonwhite >’> 

* w 

= 100 

J 

80 

El


o


–- , 66


a 

u

CL / 40 / w 

ia 

K 

20 

/ 

10 J 

8 

6 

4 I I I I I I I I I I I 

I,CXM (ool- lj?51- 1,501- [,75 1- 2,001 - 2,251- 2#01- 2,751 - 3,001 - 3,501 - 4,001- 4,501 

Or I*SS 1,250 1,500 1,750 2,000 2~50 2300 2,750 3,OOO 3300 4,000 4,500 or mort 

BIRTH WEIGHT (in warns) 

See note on figure 2,. 

of similarity to the pattern shown by the rates for 

white births. However, it will be noted that the gap 

between the ltnes representing white and nonwhite 

rates in figure 3 widens as the weights increase from 

1,000 grams or less to 1,501-1,750. In view of the 

semilogarithmic scale used, this indicates a relatively 

steeper rate of decltie h“ nonwhite mortality over the 

wei@t interval. The drop in mortality among nonwhite 

btrths was so sharp that the rate in the weight group 

1,501-1,750 was approximately the same’ as for white 

babies in the next higher 250 gram interval. After 

2,000 grams, however, the rate of decline was generally in favor of the white births, and the mortality 

curves for white and nonwhtte single btrths occurring 

in hospitals cross fn the neighborhood of 2,75o grams. 

The curves then diverged rapidly. 

The influence of gestation age on neonatal mortality was examtned for as at-curate a set of detailed 

data as is now available on a nationwide basis. These 

statistics relate to single white births delivered in 

hospitals. To avoid irregularities tn the series due 

to small frequencies and known deficiencies, consideration was limited to three gestation-age intervals 

(23-31, 32-35, and 37 weeks and over) over the weight 

span 1,501 to 3,500 grams. 

Figure 4 illustrates how important a factor gestation age was, particularly when the birth weight 

approached the upper weight level of immaturity. In 

the we:ght group 1,501-1,750, the loss among infants 

of gestations of 37 weeks and over was about twothirds the mortality tn the 28-31 weeks group. With 

increasing weight, the mortality rate declined sharply 

in each of the gestation groups. But, the decrease was 

so much more rapid among the babies who were 

mature according to the gestation criterion tht the 

rate for thts group at weight 2,251-2,500 grams was 

only one -ftfth the corresponding figure for babies 

of 23-31 weeks. of gestatiom In fact, mortalitg among 
----

----

----

----

----

----

24 VITAL STATISTICS-SPECIAL REPORTS 

FIGURE 4 

SUMMARY 

NEONATAL MORTALITY RATES AMONG SINGLE WHITE 

BIRTHS IN HOSPITALS, BY DETAILED BIRTH WEIGHT 

Statistics on maturi~ at birth derived from vital AND SPECIFIED GESTATION GROUPS: UNITED STATES, records relating to babies born in the United States 

JANUARY I TO MARCH 31, 1950 durhg the first 3 months of 1950 and neonatal deaths 

among this group, provided the following information; 400 

‘h 

.. 1. Of tie total number of children born, 7.4 percent weighed 2,500 grams or less. Nonwhite %. babies weighed on the average 50 grams less .. 

“i than the white, and greater proportions of non­ .. 

... white infants were born at the very low and g 100 — %—


1- %. very high weights where the mortality risk is


Ix 80 %. greatest. Over one-half of the liveborn chil­
 z %.. dren in plural deliveries weighed 2,500 grams
 u 60 ~ \ or less as compared with only 6.4 percent in
 ... J %. single births. Female babies weighed on the 

0 40 average 130 grafns less than male. 0 

_. 

c 

... 

%. 

% 

..% 37 weeks ond over 

2. Median weights for children in single births 

were less than 2,500 grams at gestation age u 

c1 %../ groups under 36 weeks, and were over 2,500 

grams at gestations of 3’7 weeks and over. 

However, appreciable. proportions of the children at some of the gestation ages considered 

premature weighed over 2,500 grams, and 

about half of the infants below this weight were 

reported as born at or near full term. 

6 

=..%..%. 

%; 

3. The neonatal mortality rate among infant$ 

weighing 2,500 grams or less at birth was 

173.7 per 1,000 as compared with 7.8 per 

1,000 among all other children. Mortality 

0 

1,501 - I,75L 2,001. 2,251- 2,501 - 2,751- 3,001. declined sharply with relatively small in- 1,750 2,000 2,250 2,500 2,750 3,090 3,500 

creases in weight until well past the pre- BIRTH WEIGHT (i. grad maturity weight level with the optimum weight , See no?e on figure 2. for survival falling at 3,501-4,000 grams. 

Marked increase in weight beyond this point 

was an important liability. At the low weights 

where the risk of mortalitj is great, nonwhite 

the latter group of infants was as high as the rate infants had a somewhat better chance for 

for infants of gestation ages of 37 weeks and over survival than the white. However, at almost 

who weighed 500 grams or less at birth. The same all of the mature weights the risk among nondisparity continued well into the mature weight groups white births was considerably higher. Moras indicated by the following: tality among plural births was below that 

among single births at the weights between 

1,001 and 3,000 grams but higher at weights 

28-31 32-35 37 weeks above 3,000 grams. At all “but the very high 

weeks weeks and over andvery low weights, the mortality risk was far 

greater for male births than for female. The 

1,501-1,750 grams . ..- 382.9 253.8 243.9 over-all neonatal mortality rate among males 

1,751-2,000 grams 315.3 192.8 115.2 was about one-third above the rate for fe2,001-2,250 grams 195.5 108.2 57.7 males. 

2,251-2,500 grams 125.4 71.9 27.0 4. Children born in hospitals weighed on the .aw 

2,501-2,750 grams 103.4 52.3 13.9 erage less at birth than those delivered at 

2,751-3,000 grams 76.1 44.4 7.4 home (part of this difference may be due to 

3,001-3,500 grams 40.5 23.1 5.5 biases in reporting in the nonhospital group). 
---

---------------------

-----------------

Vol. 39, No. 1 WEIGHT AT BIRTH 

Mortality among white infants delivered by 

nonmedical persons was two to four times 5. 

hat for hcspital deliveries at all weights above 

2,000 grams. Among nonwhite births, the 

rates for hospkd deliveries were substantially 

lower than those for midwife deliveries 

at weights of 1,501 to 3,000 grams, but were 

much higher at weights above 4,500 grams. 

The latter suggests a selectivity of difficult 

REFERENCES 

25 

cases for referral to hospitals.


Gestation age as well as birth weight has a


considerable influence on the survival of the


newborn. Generally, the heavier babies at


each gestation age level fared better than


the lighter ones; and sfmilarly among chil­


dren falling in the same weight group, those


at gestations at or near term bad the most


favorable mortality experience.


The most complete set of referencesavailabletoday on studies related to birth weight and gestation


age isfoundinDr. Ethel C. Dunham’s book, “PrematureM-t” (Edition2,Paul B. Hoeber, Lnc., Publishers,


in Press). A selectedgroup of referencesvhich are particularlyrelevantto a number of the statements


made in this ccrticlefollows:


(1)


(2)


(3)


(4)


(5)


(6)


(7)


(8)


McKeown,Thomas, and Gibson, J. R., “Observations on AU Births (23,970)in Birmingham,1947,”


British JournalaF Social Medicine,vol. 4(4), pp. 221-233,October 1950; vol. 5(2), pp. 98-112,


April 1951; vol. 5(3), pp. 177-183, July.1951; also, British Medical Journal,pp. 513-517, Sep­


tember 1951.


l!aback,Matthew, “BirthWeight ad Length of GestationWith Relationto Prematurity,
” The Jour­


nal of the American MecllcalAssociation,vol. 146, pp. 897-901, July 7, 1951.


Bunfiesen, Herman l’?.,
 et al., ‘!Progressin the Preventionof Needless NeonatalDeaths,” Annual


Report of the ChicagoHealth Department,1951.


Potter, Edith L., anclFuller, HarolFi, “MultiplePregnancies at the Chicago Lying-InHospital


1941to 1947,” American Journalof Obstetricsand G~ecology, vol. 58(1), pp. 139-146, July 1949.


Eastman, Nicholson J., “Prematurity From the Viewpoint of the Ob’ztetric
 ian,” Americen Practi­


tioner, vol. 1(7), pp. 343-352,March 1947.


Amierson,Nina A., Brown, Estelle W., anfiLyon, R. A., “Causes of Prematurity,
” American Jour­


nal of Diseases of children,vol. 65(4), pp. 523-534,April 1943.


Public Health Conferenceon Records anfiStatistics,AssociationcfMaternal.and Child Health anfi


Cripplefi Children Directors,FeileralSecurity Agency-Ohild.ren’
 a Bureau anfiNational Office of


Vital Statistics,“Recommendationsfor DevelopingComparableStatisticson PrematurelyBorn In- ,,


fants =tl Neonatal Mortality,” National Office Vital Statistics,1950.


—9—— “Suggestecl
 Tabulationsd!Statisticsm Birth Weight anfiRelatefiCEar­


acteristics for Live Birt~s amilNeonatalDeaths,” National Office of Vital %atistics, 1952.


SYMBOLS USEO IN SPECIALREPORTS


Class or item not applicable (threefiots)----------------------------...


Data not available (threedashes)------------------------------------


Quantity Is zero, in frequencytables (one dash) -


Quantity is zero, in rate or percent tables (one cipher)------------- o


If rate or percent is more than O but less than 0.05 0.0


If both frequencyemfipopulationbase are zero in rate or percent


tables (one aash)---------------------------------------------------

-----------------------

-------------------------

-----------------------

-------------------------

-------------------------

-----------------------

-----------------------

2,6 VITAL STATISTICS-SPECIAL REPORTS 

TASLE 1. LIVE BIRTHS AND NEONATAL DEATHS, BY BIRTH WEIGHT, RACE, SEX, AND PLUFALITY: UNITED STATES, 

JANUARY 1 TO K4.RCS31, 1950 

(Neonatal deaths include deaths within the first 28 days after birth among children born Jan. 1 to M&. 31, 1950.


Births and deaths with birth weight not stated are distributed. Excludes data for Massaohusetts)


BIRTS WEIGHT


(IN GR4MS)


All weights-----------------


000 or less 

1 001-1,500-------------------------

1,501-2,000-------------------------

2,001-2,500-------------------------

2,501-3,000-------------------------


3,031-3,500-------------------------


3,501-4,000-------------------------


4,001-4,500


4,501 or more


All weights-----------------


1,000 or less-----------------------

1,001-1,500-------------------------

1,501-2,000-------------------------

2,001-2,500-------------------------

\


2,501-3,000-------------------------


3,001-3,500-------------------------


3,501-4,000


4,001-4,500


4,501 or more-----------------------


All weights-----------------


1,000 or less 

1,001-1,500-------------------------

1,501-2,000--------------------------

2,001-2,500-------------------------

2,501-3,000-------------------------


3,001-3,500-------------------------


3,501-4,000-------------------------


4,001-4,500-------------------------


4,501 or more


BIRTSS NEONATAL DEATHS


White Nonwhite White Nonwhite


Male Female Male Female Male Female Male Female


TOTAL


368,37S 348,755 61,128 59,525 

1,621 1,568 393 346 

2,121 1,958 465 537 

4,480 4,726 1,021 1,161 

15,034 18,426 3,433 4,347 

54,833 72,073 11,211 13,691 

133,719 139,566 21,149 21,195 

112,366 86,023 15,561 12,789 

35,564 20,189 5,172 3,583 

8,640 4,226 2,723 1,876 

7,952 I 5,569 1,799 I 1,421
 1 

I I 

1,467


1,364


1,218


1,039


873


1,021


533


244


93


1,350 334 273 

929 244 264 

758 240 187 

654 206 179 

655 223 161 

682 231 17s 

349 190 108 

130 68 41 

62 63 30 

4,971 1,601 1,265 

1,093 279 233 

751 201 218 

656 179 153 

615 187 158 

645 213 150 

674 224 176 

345 188 107 

130 67 40 

62 63 30 

I 

598 198 156 

257 55 40 

178 43 46 

102 61 34 

39 19 21 

10 10 11 

8 7 2 

4 2 1 

1 1 

SINGI.E


361,233 341,733 59,583 I 58,069 I 7,212 

1,352 1,278 325 288 1,222 

1,775 1,533 374 446 1,151 

3,599 3,600 809 938 1,060 

13,018 16,304 3,011 3,892 953 

52,630 70,033 10,793 13,295 $47 

132,559 138,715 20,912 21,030 1,013 

112,138 85,890 15,488 12,742 631 

35,528 20,155 5,154 3,566 242 

8,634 4,225 2,717 1,872 93 

IN PLUPAL SETS


I 

7,145 7,022 1,545 1,456 740 

269 290 68 58 245 

346 425 91 91 213 

881 1,126 212 223 158 

2,016 2,122 422 455 86 

2,203 2,040 418 396 2s 

1,160 851 237 165 8 

228 133 73 47 2 

36 34 18 17 2 

6 1
 61 41 -1 -1 -1 -
----

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------------------

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Vol. 39, No. 1 .=WEIGHT AT BIRTH 27 

TABLE 2. LIVE BIRTHS BY BISTS WEIGHT, WEEKS OF G2S9XCION, RACE, SEX, AND PLURALITY: UNIIEIlSTATES


JANUARY 1 TO MARCH 31, 1950


(Births with birth.weight or gestation not stated are distributed. Excludes births to residents of Massachusetts)


BISTB WEIGET


(IN GRAMS)


AND SEX


Both sexes--------


1,000 or less-------------


1,001-1,500---------------


1,501-2,000---------------


2,001-2,500---------------


2,501-3,000---------------


3,001-3,500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or mOre


Male


1,000 or less 

1,001-1,500---------------

1,501-2,000---------------

2,001-2,500---------------

2,501-3,000---------------


3,001-3,500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or mOre


Female----------------


1,000 or less-------------


1,001-1,500---------------


1,501-2,000---------------


2,001-2,500---------------


2,501-3,000---------------


3,001-3,500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or mOre


> 

Both sexes--------


1,000 or less-------------


1,001-1,500---------------


1,501-2,000---------------


2,001-2,500---------------


2,501-3,000---------------


3,001-3,500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or mOre


Male


1,000 or less-------------


1,001-1,500---------------


1,501-2,000---------------


2,001-2,500---------------


2,501-3,000---------------


3,001-3,500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or mOre


WHITE NONWHITE


37 37
 Under Under
 28-31 32-35 36 weeks 28-31 32-35 36 weeks
 28 28
 weeks weeks weeks and weeks weeks weeks end
 weeks weeks
 over over


!lY3TAL BIRTES 

—-

4,064 6,024 14,537 55,796 636,712 965 1,564 2,522 15,039 100,563 

2,415 584 108 14 68 507 155 30 16 31 

1,123 1,616 869 151 320 261 404 172 47 118 

261 1,975 3,232 1,262 2,476 90 530 591 304 667 

65 1,098 4,8S5 5.,507 21,905 26 299 848 1,384 5,223 

56 323 2,902 10,579 113,046 19 79 423 2,636 21,745 

83 219 1,684 18,753 252,546 19 50 299 4,615 37,361 

44 1%5 619 14,039 183,562 31 28 100 3,837 24,354 

15 68 199 4,270 51,201 3 15 44 1,403 7,290 

2 16 39 1,221 11,5ss 9 4 15 797 3,774 

2,1S9 3,255 7,“641 28,597 326,696 506 770 1,189 7,627 51,036 

1,242 289 49 10 31 267 86 16 9 ls 

647 862 413 72 127 128 178 79 25 55 

164 1,071 1,609 567 1,069 45 260 269 146 301 

38 639 2,584 2,708 9,065 15 157 399 630 2,232 

24 166 1,581 4,880 48,182 16 45 192 1,253 9,705 

44 111 942 9,165 123,457 9 26 151 2,267 18,696 

21 67 328 7,731 104,219 19 13 51 2,037 13,441 

s 41 111 2,676 32,728 3 4 26 794 4,345 

1 9 24 7ss 7,818 4 1 6 466 2,246 

1,875 2,769 6,896 27,199 310,016 459 794 1,333 7,412 49,527 

1,173 295 59 4 37 240 69 14 7 16 

476 754 456 79 193 133 226 93 22 63 

97 904 1,623 695 1,407 45 270 322 158 366 

27 459 2,301 2,799 12,840 11 142 449 754 2,991 

32 157 1,321 5,699 64,864 3 34 231 1,383 12,040 

39 X08 742 9,588 129,089 10 24 148 2,348 18,665 

23 58 291 6,308 79,343 12 15 49 1,800 10,913 

7 27 88 1,594 18,473 u 18 609 2,945 

1 7 1.5 433 3,770 5 3 9 331 1,52S 

SINGLE BIRTHS 

3,515 5,277 12,929 54,056 627,189 827 1,420 2,277 14,602 98,526 

2,029 449 82 11 59 419 127 25 14 28 

998 1,337 666 97 210 22d 364 137 28 67 

236 1,716 2,621 923 1,703 85 468 4s5 241 458 

60 1,037 4,340 4,788 19,097 20 290 773 1,227 4,593 

53 313 2,723 10,153 109,421 17 77 397 2,523 21,074 

80 ’218 1,646 18,593 250,737 19 50 293 4,558 37,022 

43 124 616 14,009 183,236 31 26 99 3,818 24,256 

14 67 196 4,261 51,145 3 14 43 1,398 7,262 

2 16 39 1,221 11,581 9 4 1.s 795 3,766 

1,909 2,869 6,823 27.728 321,904 429 695 1,068 7.399 49,992 

1,060 218 39 7 28 221 70 11 9 14 

574 732 322 47 100 108 160 62 13 31 

148 935 1,334 428 754 42 227 226 112 202 

35 599 2,2S3 2,332 7,769 9 151 363 549 1,939 

22 i59 1,471 4,661 46,317 14 43 174 1,199 9,363 

42 111 914 9,083 122,409 9 26 149 2,236 18,492 

20 66 326 7,711 104,015 19 13 51 2,023 13,382 

7 40 110 2,671 32,700 3 4 26 793 4,328 

1 9 24 788 7,812 4 1 6 465 2,241 
----------------

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---------------

-------------

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28 VITA L STATISTICS—SPECIAL REPORTS 

TABLE 2. LIVE BIRTHS BY BIRTH WEIGHT, WEEKS OF GESTATION, RACE, SEX, AND PLURALITY: UNITED STATES, 

JANUARY 1 TO MARCH 31, 1950—Cent inued 

(Births with birth weight or gestation not stated me distributed. Excludes births to residents of Massachusetts)


WHITE NONWHITE 

BIRTS WEIGET
 37 37
 (IN Gm4s ) Under 2S-31 32-35 36 weeks Under 28-31 32-35 3s
 weeks
 AND SFX 2s 2s
 weeks weeks weeks and weeks weeks weeks end
 weeks weeks
 over over


SINGLE BIRTHS—Continued


2,501-3,000--------------- 31 154 1,252 5,492 63,104 3 34 223 1,324 11,711 

3,001-3,500--------------- 38 107 732 9,510 128,328 10 24 144 2,322 18,530 

3,501-4,000--------------- 23 58 290 6,29S 79,221 12 13 48 1,795 10,874 

4,001-4,500 7 27 86 1,590 18,445 10 17 605 2,S34 

4,501 

Female 1,606 2,408 6,106 26,328 305,285 398 725 1,209 7,203 48,534 

1,000 or less------------- 969 231 43 .4 31 198 57 14 5 14 

1,001-1,500 424 605 344 50 110 116 204 75 15 36 

1,501-2,000--------------- 8S 781 1,2S7 495 949 43 241 269 129 256 

2,001-2,500--------------- 25 43s 2,057 2,456 11,32S 11 139 410 678 2,654 

or more T1
 7 15 433 3,769 5 3 9 330 1,525

BIRTHS IN PLUBAL SETS


Both sexes-------- 549 747 1,608 1,740 9,523 138 144 245 437 2,037 

1,000 or less 3S6 135 26 3 9 8S 28 5 2 3 

1,001-1,500 125 279 203 54 110 37 40 35 19 51 

1,501-2,000--------------- 25 259 611 339 773 5 62 96 63 209 

2,001-2,500 5 61 545 719 2,808 6 9 75 157 630 

2,501-3,000--------------- 3 10 179 426 3,625 2 2 26 113 671 

3,001-3,500--------------- 3 1 38 160 1,809 6 57 359 

3,501-4,000--------------- 1 1 3 30 326 2 1 19 S8 

4,001-4)500--------------- 1 1 3 9 56 1 1 5 28 

4,501 or mOre 7 2 8 

Male 280 386 818 869 4,792 77 75 121 228 1,044


1,000 or less 182 71 10 3 3 46 16 5 1 

1,001-1,500 73 130 91 25 27 20 18 17 12 24 

1,501-2,000--------------- 16 136 275 139 315 3 33 43 34 99 

2,001-2,500--------------- 3 40 301 376 1,296 6 6 36 81 293 

2,501-3,000--------------- 2 7 110 219 1,865 2 2 18 54 342 

3,001-3,500--------------- 2 28 82 1,048 2 31 204 

3,501-4,000--------------- 1 1 2 20 204 14 59 

+,001-4,500--------------- 1 1 1 5 28 ~. - 1 17 

4,501 or mOre 6 1 5 

Female---------------- 269 361 790 871 4,731 61 69 124 209 993 

1,000 or k=s------------- 204 64 16 6 42 12 2 2 

1,001-1,500--------------- 52 149 112 29 83 17 22 18 7 27 

1,501-2,000--------------- 9 123 336 200 458 2 29 53 29 110 

2,001-2,500--------------- 2 21 244 343 1,512 3 39 76 337 

2,501-3,000--------------- 1 3 69 207 1,760 8 59 329 

3,001-3,500--------------- 1 1 10 7s 761 4 26 135 

3,501-4,000--------------- 1 10 122 2 1 5 39 

4,001-4,500--------------- 2 4 28 1 1 4 11 

4,501 or more 1 1 3 
-------------

---------------

---------------

---------------

-------------

---------------

-------------

---------------

-------------

---------------

---------------

---------------

-------------

-------------

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Vol. 39, No. 1 WEIGHT AT BIRTH 29 

TmIal 3. NEOMW’ALDEATSS BY B16TE WEIGHT, NEXKS OF GELYLATION,RACE, Sl!x, AND TmRAmrY: UNITELI STATES, JANUARY 1 TO MARCH .31, 1950


(Includes deaths within the first 2S days after birth among children born San. 1 to Mar. 31, 1950. Deaths with


birth veight or gestation not stated ere distributed. ExcludeB data for Massachusetts)


WHITE! NONWHITE 

BIRTE WEIGST
 37 37
 (IN GRAMS) Under 28-31 32-3.5 36 weeks Under 2831 32-35 36 weeks AND SEX 28 28 weeks weeks weekB alla veeka weeks weeke Sna weeks weeks 

Both sexes--------


1,000 or less


1,001-1,500---------------


1,501-2,000


2,001-2,500


2,501-3,000---------------


3,001-3,500---------------


3,501-4,000


4,001-4,500---------------


4,501 or more


Male------------------


1,000 or less-------------


1,001-1,500---------------


1,501-2,000---------------


2,001-2,500


2,501-3,000---------------


3,0013,500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or more


Female----------------


1,000 or less-------------


1,001-1,500---------------


1,501-2,000


2,00!i-2,500---------------


2,501-3,000---------------


3,001-3>500---------------


3,501-4,000---------------


4,001-4,500---------------


4,501 or more


Both sexes--------


1,000 or less-------------


1,001-1,500


1,501-2,000


2,001-2,500


2,501-3,000---------------


3,001-3,500---------------


3,501-4,0C&--------------


4,001-4,s00----------------


4,501 or more


Male------------------


1,000 or lef3s


1,001-1,500---------------


1,501-2,000


2,001-2,500---------------


2,501-3,000


3,001-3,500---------------


3,501-4,COB---------------


4,001-4,500---------------


4,501 or mOre


over


3,266 2,337 1,779 1,008 5,3.31 699 542


2,209 484 S5 

656 905 362 

155 683 662 

26 206 453 

6 35 149 

8 8 40 

2 6 7 

3 9 1s 

1 1 3 

1,808 1,398 1,086 

1,154 251 44 

519 554 195 

105 417 405 

15 137 299 

4 23 100 

6 -1 28 

2 4 3 

2 4 11 

1 1 1 

1,458 939 693 

1,055 233 41 

337 351 167 

50 266 257 

11 69 X54 

2 12 49 

2 1 L2 

2 4 

1 5 7 

2 

2,7S9 1,975 1,547 

1,851 369 64 

755 744 206 

144 603 567. 

24 201 4X8 

5 34 145 

6 8 39 

1 6 7 

2 9 18 

1 1 3 

1,563 1,197 959 

9s5 189 34 

457 468 158 

96 3S8 354 

14 134 274 

3 22 97 

5 7 27 

1 ‘4 3 

1 4 11 

L 1 1 

6 33 439 124 

.37 11.3 184 189 

180 29S 51 151 

275 733 7 57 

191 1,147 5 12 

155 1,492 1 3 

86 881 1 4 

4’1 303 2 

17 133 1 

640 3,020 380 291 

5 n 240 70 

38 58 100 93 

118 173 27 75 

172 416 6 38 

121 625 5 8 

96 8S4 1 3 

55 569 1 3 

27 200 1 

8 82 

368 2,111 319 251 

1 20 129 54 

19 55 94 96 

82 123 24 76 

103 317 1 19 

70 522 4 

59 608 

31 312 1 

14 103 1 

9 51 1 

AMONS SINGLE Bml!ss


923 4,949


3 28


34 83


El 251


250 675


189 1,119


152 1,482


86 876


41 302


17 133


579 2,914


2 12


21 47


98 144


1.55 376


120 605


93 881


55 ,5ss


27 199


8 ’82


594 I 472


T

374 103


163 171


48 L24


2 57


4 12


1 3


1 1


1


1


319 I 250


T

204 56


84 84


24 59


1 38


4 8


1 3


1 1


1


over


291 296 1,392


23 8 13 

66 18 41 

92 43 90 

73 76 172 

L9 35 313 

a 52 345 

4 36 253 

5 15 87 

1 13 78 

153 164 811 

13 5 6 

27 6 18 

57 32 49 

31 34 97 

10 20 180 

7 26 194 

2 22 162 

5 8 54 

1 11 51. 

138 132 581 

10 3 7 

39 12 23 

35 11 41 

42 42 75 

9 13 133 

1 26 151 

2 14 91 

7 33 

2 27 

248 2s1 1,291 

17 6 12 

54 8 23 

75 35 50 

68 63 155 

16 33 298 

8 52 336 

4 36 253 

5 I-5 86 

1 13 78 

129 146 757 

8 5 6 

22 1 10 

4s 24 26 

29 30 89 

9 19 173 

7 26 187 

2 22 162 

5 8 53 

1 11 51 
----------------

-------------

---------------

---------------

-------------

---------------

---------------

---------------

------------------

---------------

---------------

---------------

-------------

30 VITAL STATISTICS-SPECIAL REPORTS 

TABLE 3. NZOit4TAL DEATSS BY BIRTH WEIGHT, WEEKS OF GESTATION, BACE, SEX, AND PLURALIIZ: UNITED STATES, 

JANUARY 1 TO MARCH 31, 1950-Continued


(Eke headnote on p. 29)


WHI!EZ NONWHITE


I 1 1 #
 BIRTH WEIGST
 37 37
 (IN GRAMS) Under 28-31 32-35 36 Un6er 28-31 32-35 36
 AND SEX 28 weeks 2s weeks 

weeks weeks weeks weeke and weeks weeks weeks weeks and


over over


MOW SIICLE BISTHS-Cent inued


4’--= 1,000 or less S66 180 30 1 16 170 47 9 1 6 1,001-1,500 298 276 128 13 36 79 07 32 7 13 1,501-2,000 48 235 213 53 107 24 65 29 11 24 

2,001-2,500--------------- 10 67 144 95 299 1 19 39 33 66 

Female 7-IS 58s 344 2,035 27’5 222 119


2,501-3,0CK3--------------- 2 12 48 69 514 4 7 14 125 

3,001-3,500--------------- 1 1 12 59 601 1 26 149 

3,501-4,000---------------

1,226 T4 31 30s 

1 r2 I 27 

2 2 14 91
 4,001-4,500--------------- 1 5 7 14 103 -


2 T51 L. 7 33 

4,501 or more 9 

AMONG BIRTHS IN PLURAL SETS


Both sexes-------- 477 362 232 1s2 7( 101


1,000 or les8------------- 35E 115 21 ~ 65 2: 2 1 

l,ool-l,5m 101 161 76 3C 31 1< lC 1s 

1,501-2,”000--------------- 11 80 95 45 3 2; e 40 

2,001-2,500--------------- 2 5 35 5s 5 13 17 

2,501-3,000--------------- 1 1 4 28 1 2 15, 

3,001-3,500--------------- 2 1 10 9 

3,501-4,000 1 5 : 

4,001-4,500 1 1 1 1 

4,501 or more------------- -


Male 245 201 127 106 61 41 18 54 

1,000 or le8s------------- 169 62 10 3 1 36 14 5 

1,001-1,5G0--------------- 62 86 37 17 11 16 9 5 5 8 

1,501-2,000--------------- 9 49 51 20 29 3 16 11 8 23 

2,001-2,500--------------- 1 3 25 17 40 5 . 2 4 8 

2,501-3,000--------------- 1 1 3 1 20 1 1 1 7 

3,001-3,500--------------- 1 1 3 3 7 

3,501-4,000 1 1 . 2 

4,001-4,500--------------- 1 - 1 1 

4,501 or more------------- - -

Female---------------- 232 161 105 24 76 44 29 19 17 47 

1,000 or less------------- 189 53 11 4 29 7 1 2 1 

1,001-1,500 39 75 39 6 19 15 9 7 5 10 

1,501-2,000--------------- 2 31 44 9 16 11 6 17 

2,001-2,500--------------- 1 2 10 8 18 3 9 9 

2,501-3,COB--------------- 1 1 s 2 1 0 

3,ml-3,500--------------- 1 - 7 . 2 

3,501-4,000 4 1 

4,001-4,500--------------- 1 

4,501 or more -

10T 

Vol. 39, No. 1 WEIGHT AT BIRTH 31 

TABE3 4. LIVE BIRTSS AND NEONATAL ‘DEA~S,, BY BIRTE WEIGST, RACE, AND ATPENOANT AT BISTE: UNTTEO STATES,


JAIK7ARY1 TO MARCH 31, 19S0


(Neonatal deaths include deaths within the first 28 days after birth SISOIIS
children born Jan. 1 to Mar. 31, 1950.


Births and deaths with birth weight not stated are distributed. Excludes data for Massachusetts)


Am BACES II WHITE NoNwHIm 

BIRTE WEISHT


(IN GRAMS) Physician Physician M:~ ‘ Physician -’---’cian rnys 2 “:=’ Physicieu Physician Midwife,


in not in in n’ in in not in other,


and not and not and not
 hospitall hospital specified hospitall nospital specified hospitall hospital specified


BIRTHS


All weights- 725,226 65,406 47,154 65S.295 47.846 10,992 36.162 

1,000 or less--- 3,494 314 1.20 2,921 226 42 573 S8 76 

1,001-1,500----- 4,355 476 250 3,698 291 90 657 1s3 160 

l,501-2,0CM3----- 10,007 807 574 8,524 532 150 1,483 275 424 

2,001-2,500----- 36,238 2,940 2,062 30,990 1,934 536 5,246’ 1,006 1,526 

2,501-3,000----- 136,481 9,663 5,664 119,198 6,383 1,325 17,283 3,260 4)339 

3,001-3,500----- 280,371 22,052 13,206 254,291 15,919 3,075 26,0S0 6,133 10,131 

3,501-4,000----- 192,607 19,041 14,891 180,548 14,426 3,415 12,259 4,615 11,476 

4,001-4,500----- 51,437 6,904 6,167 48,746 5,576 1,431 2,691 1,328 4,736 

.,4,501or more--- 10,036 3,209 4,220 9,379 2,559 928 657 650 3,292 

NEONATAL DEATSS 

I I I 

==4== 1 I I I 

1,000 or less--- 3,083 249 92 2,602 180 35 481 69 57 

1,oo1-1,500----- 2,393 265 143 2,064 168 61 329 97 82 

1,501-2,000----- 2,038 214 151 1,803 136 37 235 78 114 

2,001-2,500----- 1,657 232 189 1,448 183 62 209 49 127 

2,501-3,000----- 1,530 227 155 1,337 143 48 193 84 107 

3,001-3,500----- 1,674 241 197 1,470 167 66 204 74 131 

3,501-4,000----- 973 136 171 857 82 43 116 54 126 

4,001-4,500----- 343 60 80 308 42 24 35 18 56 

4,501 or mOre--- 130 49 69 101 35 19 29 14 50 

All weights- 1,247 11,990 1.X56 395 I 1.831 537 852 

lIt is assumed that all births in hospitals or institutions are attended by physicians.

---------------------------------------

---------------------------------------

-------------------------------------

---------------------------------------

---------------------------------------

-------------------------------------

---------------------------------------

-------------------------------------

32 VITAL STATISTICS-SPECIAL REPORTS


TABIE 5. LIVE BISTSS ANO NEONATAL DEATSS, BY BIRTH WEIGRT, RACE, A’T&ZNDANTAT “BIRTH,AND PLUP.AUTI:


UNITEIlSTATES, JANUARY 1 TO MARCH 31, 1950


(Neonatal deaths include deaths within the first 28 days after birth among children born Jan. 1 to Mar. 31, 1950.


Births and deaths with birth weight not stated are distributed. Excludes data for Maeeachusetts)


WHITE NONWHITE 

BIRT6 KEIGWi7


(IN GRAMS) Physician Physician Midwife, Physician Physician Midwife,


in not in other, in not.in other,


end not and not
 hospitall hospital specified hospitall hoepital specified


SING~ BIRTHS


All weighte-------------------------------


1,000 or lees------------------------------------­


l,ool-l,500


1,501-2,OOO---------------------------------------


2,001-2,500---------------------------------------


2,501-3,OOO---------------------------------------


3,001-3,500--------------------------------------­


3,501-4,ooo-------------------------*------------­


4,001-4,500


4,501 or more


All weighte -------------------------------


1,000 or less------------------------------------­

l,ool-l,5m 

1,501-2,OOO---------------------------------------

2,001-2,500---------------------------------------

2,501-3;OOO---------------------------------------


3,001-3;500--------------------------------------­


3,501-4,ooo---------------------------------------


4,001-4)500---------------------------------------


4,501 or more--------------------------------—---


All weights-------------------------------


1,000 or less------------------------------------­


l,ool-l,500


1,501-2,OOO---------------------------------------


2,001-2,500---------------------------------------


2,501-3,OOO---------------------------------------


3,001-3,500--------------------------------------­


3,501-4,ooo---------------------------------------


4,001-4,500---------------------------------------


4,501 or more


All weights-------------------------------


1,000 or less------------------------------------­


l,ool-l,500--------------------------------------­


1,501-2,OOO---------------------------------------


2,OOl-2,5OO-------------------------------------a-


2,501-3,OOO---------------------------------------


3,001-3,500--------------------------------------­


3,501-4,ooo---------------------------------------


4,001-4,500


4,501 or more


645.343 46,831 10,792
 —


2,414 180 36 

2,995 231 S2 

6,661 41.5 123 

27,197 1,642 485 

115,266 6,113 1,284 

252,489 15,754 3,031 

180,253 14,379 3,’396 

48,692 5,561. 1,430 

9,376 T2,556 927 

65,202 17,094


477 72


547 151


1,213 202


4,690 8S2


16,800 3,153


25,902 6,064


12,233 4,595


2,683 1)325


657 650


NEONATAL DEATESAMONGSINGIKlBIRTHS 

10,790 1,023 370 1,635 478 

2,143 143 29 407 59 

1,711 135 56 279 76 

1,571 114 31 167 64 

1,342 169 57 192 43 

1,306 =8 48 189 77 

1,459 165 63 202 72 

851 62 43 116 53 

306 42 24 34 18 

101 35 19 I29 14 

BIRTSS IN PIURAL SETS


12,952 1,015 200 1,729 466 

507 46 6 96 i6 

703 60 8 110 34 

1,863 117 27 270 73 

3,793 292 53 558 124 

3,932 270 41 4.S3 127 

1,802 165 44 178 69 

295 47 19 26 20 

54 15 1 8 3 

3 3 1 

IC30NA!FAL
 DEMES AMONG BIRTBS IN PLURAL SETS


1,200 113 25 196 59/ 

459 37 6, 74 10 

353 33 5 5Cl 19 

232 22 6 48 14 

106 14 5 17 6 

31 5 4 7 

11 2 3 2 2 

6 1 

2 1 

35,356


64


122


332


1,331


4,155


9,976


11,402


4,712


3,282


753


46


62


81


110


97


126


126


55


50


606


14


38


92


195


204


155


74


24


10


99


11


20


33


17


10


5


2


,1


lIt is assumed that all births in hospitals or institutions are attended by physiciene.

-----------------------------

-------------------------------

-------------------------------

-------------------------------

-------------------------------

-----------------------------

Vol. 39, No. 1 WEIGHT AT BIRTH 33 

TABLE 6. SINGLE LIVE B16TES IN EOSPITAIS AND NEONATAL DEATHS AMONG THIS GROUP, BY DETAIIED BIRTH WEIG3T AND RA.m”:


UNITED STATES, JANUARY 1 ‘IDMARCH 31, 1950


(Neonatal	deaths include deaths within the first 28 days after birth amons children born Jan. 1 to Mm. 31, 1950.


Births and deaths with b trth weight not stated are distributed. Excludes data for Massachusetts )


BIRTHS 

BIRTH WEIGET 

(IN G8AMS) 

111 races Nonwhite 

All weights-----------------------


1,000 or less


1,001-1,250


1,251-1,500


1,501-1,730


1,751-2,000-------------------------------


2,001-2,250-------------------------------


2,251-2,500-------------------------------


2,50i-2,750-------------------------------


2,751-3,000-------------------------------


3,001-3,500-------------------------------


3,501-4,000-------------------------------


4,001-4,500


4,591 or more


710,545 645,343 65,202 

2,891 2,414 477 

1,607 1,371 236 

1,935 1,624 311 

2,829 2.381 448 

5,045 4;280 765 

8,664 7,521 1,143 

23,223 19,676 3,547 

49,035 42,310 6,725 

83,031 72,956 1o,075 

278,391 252,489 25,902 

192,486 189,253 12,233 

51,375 48,692 2,683 

10,033 9,376 657 

NEONATAL DEATSS 

U1 races White


12,425 10,790 1,635 

2,550 2,143 407 

1,061 916 3.45 

929 795 1.34 

842 751 91 

916 820 96 [ 

710 633 77 

824 709 115 

795 702 93 

700 604 96 

1,661 1,459 202 

967 851 116 

340 306 34 

130 101 29 

U.S. GOVERNMENT PRINTING OFFICE : 196S 0—188-637 
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