NCHS Data Brief ■ No. 306 ■ March 2018

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Singleton Low Birthweight Rates, by Race and 

Hispanic Origin: United States, 2006–2016

Lindsay S. Womack, Ph.D., Lauren M. Rossen, Ph.D., and Joyce A. Martin, M.P.H.

Key findings

Data from the National 

Vital Statistics System

● The singleton low

birthweight (less than 2,500

grams) rate increased in 2015

(6.34%) and 2016 (6.44%),

after declining from 2006 to

2014 (6.49% to 6.24%).

● The recent increase in the

singleton low birthweight rate

from 2014 to 2016 reflects

an increase in the rate of

moderately low birthweight

(1,500–2,499 grams), as the

rate of very low birthweight

(less than 1,500 grams) was

stable during this period.

● The low birthweight and

moderately low birthweight 

rates among singletons rose 

from 2014 to 2016 for each 

race and Hispanic-origin group.

● The rate of singleton low

birthweight was more than 

twice as high for non-Hispanic 

black infants as for 

non-Hispanic white infants 

from 2006 to 2016.

Low birthweight (LBW) is among the leading causes of infant death in the 

United States (1). LBW infants are also more likely to have health problems 

(2). After reaching its highest level in four decades, the LBW rate among all 

births declined from 2006 to 2014 (3,4), but the trend reversed in 2015 and 

2016 when the LBW rate increased (4), moving further away from the Healthy 

People 2020 goal of reducing LBW rates to 7.8% of live births (5). This 

report shows trends in LBW, moderately low birthweight (MLBW), and very 

low birthweight (VLBW) by race and Hispanic origin from 2006 to 2016 for 

singleton births only, as rates of multiple births can impact LBW rates (4,6).

Keywords: infant health • National Vital Statistics System

The singleton LBW rate increased in 2015 and 2016, after 

declining from 2006 to 2014.

Figure 1. Singleton low birthweight, moderately low birthweight, and very low birthweight rates: 

United States, 2006–2016 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

Quadratic trend from 2006 to 2016 is statistically significant at p < 0.05 level for very low birthweight, moderately low birthweight, 

and total low birthweight.

NOTES: Data do not add to total due to rounding. Access data table for Figure 1 at: 

https://www.cdc.gov/nchs/data/databriefs/db306_table.pdf#1.

SOURCE: NCHS, National Vital Statistics System, Natality.
NCHS Data Brief ■ No. 306 ■ March 2018

■ 2  ■

● The LBW rate rose 3% from 2014 to 2016 (6.24% to 6.44%), after declining from 2006 to

2014 (6.49% to 6.24%) (Figure 1).

● The rate of MLBW rose from 5.17% in 2014 to 5.36% in 2016, after declining from 2006 to

2014 (5.35% to 5.17%).

● The rate of VLBW was stable from 2013 to 2016 (1.08% in 2013, 1.07% in 2014, and

1.08% in 2015 and 2016).

● The decline in total LBW from 2006 to 2014 reflects the decline in both the MLBW rate and

the VLBW rate, whereas the increase in total LBW in 2015 and 2016 was due to the rise

only in the MLBW rate. 

Singleton LBW rates increased for each race and Hispanic-origin group in 

2015 and 2016.

● After declining from 11.85% in 2006 to just under 11.00% in 2013 and 2014, the LBW rate

for non-Hispanic black infants increased in 2015 (11.17%) and 2016 (11.36%) (Figure 2).

Figure 2. Singleton low birthweight rates, by race and Hispanic origin: United States, 2006–2016 Percent

 

 

 

 

 

 

 

 

 

 

 

 

1

Quadratic trend from 2006 to 2016 is statistically significant at p < 0.05 level for total and all race and Hispanic-origin categories. 2

For each year, differences in the rate across race and Hispanic-origin categories are statistically significant (p < 0.05).

NOTE: Access data table for Figure 2 at: https://www.cdc.gov/nchs/data/databriefs/db306_table.pdf#2.

SOURCE: NCHS, National Vital Statistics System, Natality.
NCHS Data Brief ■ No. 306 ■ March 2018

■  3  ■

● The rate of LBW for Hispanic infants was stable from 2006 to 2014 (5.79% in 2014) and 

then increased to 5.92% in 2015 and 6.04% in 2016.

● After declining from 5.37% in 2006 to a low of 5.10% in 2012, the rate of LBW for 

non-Hispanic white infants was essentially stable for 2012–2014, and then increased to 

5.13% in 2015 and 5.21% in 2016.

● The LBW rate was more than twice as high for non-Hispanic black infants as for 

non-Hispanic white infants throughout the entire period (11.36% compared with 5.21% 

in 2016).

For each race and Hispanic-origin group, increases in LBW from 2014 to 

2016 were largely due to increases in MLBW.

● Among non-Hispanic black infants, the LBW rate increased (from 10.97% in 2014 to 

11.36% in 2016), reflecting the increase in the MLBW rate (from 8.62% in 2014 to 8.98% 

in 2016) (Figure 3); VLBW rates remained stable during the same period.

Figure 3. Singleton low birthweight, moderately low birthweight, and very low birthweight rates, by race and Hispanic 

origin: United States, 2014–2016 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

Significant increases in total low birthweight and moderately low birthweight rates in 2016, compared with 2014 and 2015 (p < 0.05). 2

For each year, differences in the rate across race and Hispanic-origin categories are statistically significant for all low birthweight categories (p < 0.05).

NOTES: Data do not add to total due to rounding. Access data table for Figure 3 at: https://www.cdc.gov/nchs/data/databriefs/db306_table.pdf#3.

SOURCE: NCHS, National Vital Statistics System, Natality.
NCHS Data Brief ■ No. 306 ■ March 2018

■  4  ■

● Total LBW increased for Hispanic infants from 2014 to 2016 (5.79% to 6.04%), as did the 

MLBW rate (4.80% in 2014 to 5.03% in 2016); VLBW rates remained stable during the 

same period.

● Among non-Hispanic white infants, total LBW increased from 5.11% to 5.21% due to an 

increase in the rate of MLBW from 2014 to 2016 (4.33% to 4.44%). The rate of VLBW 

was stable.

● Singleton MLBW rates for non-Hispanic black infants were twice as high as the rates for 

non-Hispanic white infants throughout the study period (8.98% compared with 4.44% 

in 2016).

● Singleton VLBW rates for non-Hispanic black infants were more than three times as high as 

the rates for non-Hispanic white infants throughout the entire period (2.39% compared with 

0.77% in 2016).
NCHS Data Brief ■ No. 306 ■ March 2018

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Summary

After declining from 2006 to 2014, the rate of singleton LBW increased in the United States in 

2015 and 2016. The increase in singleton LBW was attributable to increases in MLBW, as VLBW 

rates were stable. Increases in the rates of singleton overall LBW and MLBW are evident for 

the three largest racial and ethnic subgroups: non-Hispanic black, Hispanic, and non-Hispanic 

white. For each race and Hispanic-origin group, the increases in singleton LBW were primarily 

driven by increases in MLBW births. Restricting this analysis to singleton births revealed similar 

trends in LBW among singletons compared with trends of LBW among all births (singletons and 

multiples) from 2006 to 2016 (4).

Definitions

Low birthweight rate: Number of births delivered at less than 2,500 grams per 100 births.

Moderately low birthweight rate: Number of births delivered between 1,500 grams and 

2,499 grams per 100 births.

Very low birthweight rate: Number of births delivered at less than 1,500 grams per 100 births.

Race and Hispanic origin: Race and Hispanic origin are reported separately on birth certificates. 

Persons of Hispanic origin may be of any race. Persons of non-Hispanic ancestry are further 

classified by race because there are substantial differences in fertility and maternal characteristics 

between Hispanic and non-Hispanic persons. Multiple-race data reported since 2003 were bridged 

to single-race categories for comparability among states and for trend analyses.
NCHS Data Brief ■ No. 306 ■ March 2018

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Data source and methods

This report is based on data from the Natality Data File from the National Vital Statistics System. 

The vital statistics natality file is based on information derived from birth certificates and includes 

information for all births occurring in the United States. The vital statistics natality file is the 

primary data set for analyzing birth trends and patterns in the United States. Natality data sets are 

available from: https://www.cdc.gov/nchs/data_access/vitalstatsonline.htm.

Computations exclude records for multiple births (3.44%) and records for which information 

on birthweight is unknown (0.10%). Linear and quadratic trends over time were tested using 

orthogonal polynomials. All differences reported are statistically significant at the p < 0.05 level 

using a z test for difference of proportions (4). Data management and statistical analyses were 

conducted using SAS system for Windows version 9.4 (SAS Institute, Inc., Cary, N.C.).

About the authors

Lindsay S. Womack is with the Centers for Disease Control and Prevention’s Epidemic 

Intelligence Service, assigned to the National Center for Health Statistics (NCHS) Division of 

Vital Statistics. Lauren M. Rossen and Joyce A. Martin are with NCHS’ Division of 

Vital Statistics.
NCHS Data Brief ■ No. 306 ■ March 2018

■  7  ■

References

1. Heron M. Deaths: Leading causes for 2015. National Vital Statistics Reports; vol 66 no 5. 

Hyattsville, MD: National Center for Health Statistics. 2017.

2. March of Dimes. Low birthweight. White Plains, NY. Available from: 

https://www.marchofdimes.org/complications/low-birthweight.aspx. 

3. Martin JA, Hamilton BE, Sutton PD, Ventura SJ, Menacker F, Kirmeyer S, Mathews TJ. 

Births: Final data for 2006. National Vital Statistics Reports; vol 57 no 7. Hyattsville, MD: 

National Center for Health Statistics. 2009.

4. Martin JA, Hamilton BE, Osterman MJK, Driscoll AK, Drake P. Births: Final data for 2016. 

National Vital Statistics Reports; vol 67 no 1. Hyattsville, MD: National Center for Health 

Statistics. 2018.

5. U.S. Department of Health and Human Services. Healthy People 2020. Maternal, infant, 

and child health. Available from: https://www.healthypeople.gov/2020/topics-objectives/topic/

maternal-infant-and-child-health/objectives. 

6. Blondel B, Kogan MD, Alexander GR, Dattani N, Kramer MS, Macfarlane A, Wen SW. 

The impact of the increasing number of multiple births on the rates of preterm birth and low 

birthweight: An international study. Am J Public Health 92(8):1323–30. 2002.
NCHS Data Brief ■ No. 306 ■ March 2018

Suggested citation

Womack LS, Rossen LM, Martin JA. 

Singleton low birthweight rates, by race and 

Hispanic origin: United States, 2006–2016. 

NCHS Data Brief, no 306. Hyattsville, MD: 

National Center for Health Statistics. 2018.

Copyright information

All material appearing in this report is in 

the public domain and may be reproduced 

or copied without permission; citation as to 

source, however, is appreciated.

National Center for Health 

Statistics

Charles J. Rothwell, M.S., M.B.A., Director

Jennifer H. Madans, Ph.D., Associate 

Director for Science

Division of Vital Statistics

Delton Atkinson, M.P.H., M.P.H., P.M.P., 

Director

Hanyu Ni, Ph.D., M.P.H., Associate Director 

for Science

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