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FROM VITAL & HEALTH STATISTICS OF THE NATIONAL CENTER FOR HEALTH STATISTICS 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE � Public Health Service I Number20¤ March 13,1978 

Office Visits to Obstetrician-Gynecologists: 

National Ambulatory Medical Care Survey, United States, 19751 

During 1975 an estimated 48 million visits 

were made to the offices of obstetriciangynecologists practicing in the coterminous 

United States. The data presented in this report 

were collected during calendar year 1975 in the 

Nat ionaI Ambulatory Medical Care Survey 

{ NAMC S ), a continuous survey conducted 

yearly by ‘the National Center for ‘Health Statistics. 

@ The estimates presented are based on information obtained f;om the Patient Record used 

by sample physicians to record selected information about their office encounters. (See Technical Notes.) Since the statistics for this report are 

based on sample data, they are subject to sam1Thisreportwas preparedby TrenaEzzati,
 Division 

of Health Resources Utilization Statistics. 

Table 1. Number and percent distribution of


pling variability. Further discussion of sampling 

variability and the sample design used in the 

1975 NAMCS appears in the Technical Notes. 

DATA HIGHLIGHTS 

During 1975 there were an estimated 567.6 

million visits made to the offices of office-based 

patient care physicians practicing in the coterminous United States. The estimated total 

yezuly volume of office-based ambulatory medical care by specialty is shown in table 1. In 

terms of total o f fice visits, obstetriciangynecologists ranked third among all physician 

specialties with 48,076,000 visits. 

Thirty-nine percent of the visits to obstetrician-gynecologists were to those in practice by 

office visits by
..-~hvsician s~ecialtv:


United States, 1975


Number


of visits Percent


Physician specialty distribution


of vis its
 thou;~nds 1


All specialties I 567,600 I 100.0 

General and family practice 234,660 41.3


Internal medicine 62,117 10.9


OBSTETRICS -HMCOLOH 48,076 8.5


Pediatrics 46,684 8.2


General surgery 41,292


All other 134,771 2;::


e ‘Due to a refinement of the NAMCS estimating procedure used to project national es­


timates from sample data,caution should be used when comparing these estimated numbers


of office visits with previously published estimates for 1973 and 1974.


8 
Figure 1. PERCENT OF OFFICE VISITS TO OBSTETRICIANGYNECOLOGISTS BY AGE OF PATlENT: UNITEO STATES, 

1975. 

I 51 

Under 15 15.24 25.44 4544 65 and 

over 

AGE IN YEARS 

themselves, and the remaining 61 percent were 

to those practicing in a group or partnership 

arrangement. 

Office visits made by females in the childbearing interval, 15-44 years, accounted for 85 

percent of the total number of visits to obstetrician-gynecologists (figure 1), naturally reflecting, 

the most common reason for visits to obstetric ian-gynecologists -prenatal examinations and 

care. 

The most frequent reasons patients had for 

their visits are ranked according to their order of 

frequency in table 2. The top six reasons 

account for about 68 percent of all visits to 

obstetrician-gy necologists. In contrast, 36 patient problems are required to account for a 

comparable 68 percent of the visits to general 

and family practitioners. 

Data on the physician’s assessment of the 

seriousness of the patient’s problem (in terms of 

the extent of impairment that might result if no 

care were obtained) indicate that less than 1 in 

10 (7.7 percent) of the visits to obstetrician @ 

Table 2. Number, percent, and cumulative percent of office visits to obstetrician-


gynecologists, by the most common patient problems, complaints Y or sYmPtoms f United


States, 1975


[Symptomtitles
 andcode numbers are based on a symptom 

Most common patient problems, complaints,


or symptoms and NAMCS code


Pregnancy examination, routine ---------------9O5 

Gynecological examination --------------------9O4 

Vaginal discharge ----------------------------662 

Surgical aftercare---------------------------986 

Menstrual disorders --------------------------653 

Abdominal pai.n-------------------------------54O 

Vaginal disorders ----------------------------66l 

Vulvar disorders -----------------------------663 

other symptoms referable to the female 

reproductive system- -~----------------------67O


Visit for fanily planning services—


counseling----------------------------------93O


Pelvic symptoms ------------------------------660


Visit for family planning services—


medication- ---------------------------------931


None -----------------------------------------997


Visit for family planning services—


services------------------------------------932


Menopause symptoms ---------------------------650


classification developed for usein NAMCS] 

Number of Cumulative


Percent of
 visits in percent


thousands visits 1 of visits


15.901 33.11 33.1 

7;596 15.8 48.9 

2,952 6.1 55.0 

2,803 5.8 60.8 

2.184 4.5 65.3 

1;323 68.1 

941 ;:: 70.1 

784 1.6 71.7 

775 1.6 73.3 

683 1.4 74.7 

655 1.4 76.1 

584 1.2 77.3 

528 1.1 78.4 

514


511


1 

Based on a total of 48,076,000 office visits.

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adwlncedata 3 

Table 3. Percent distribution of office


visits to obstetrician-gynecologistsby


physician’s assessment of seriousness


of patient’s problem: United States,


1975


Percent
 Seriousnessof distribution
 patient’s problem of visits


Serious or very serious---


Slightly serious J:;


Not serious 76.6


gynecologists
were consideredseriousor very 

serious innature(table
3).

Data onthepatient’spriorvisit
statusshow 

that about 86 percentof allvisitsto obstetri­


cian-gynecologists
 were made by patientswho


had seenthephysickin before(table
4).Obstetri­


cian-<gynccologkts alsodealtchiefly
witholdpa­


tientproblems.The proportionofnewproblems


�

-presentedto obstetrician-gynecologists
 by old


patients(18 percent)was slightly
 lessthan the


Table 4. Percent distribution of office


visits to obstetrician-gynecologistsby


patient’s prior visit status: United


States, 1975


I 

Percent
 Patient’s prior visit distribution
 status
 of visits


New patient 14.2


Old patient, new problem-- 18.0


Old patient, old problem-- 67.9


correspondingproportionforallphysicians
(23


percent).


Informationconcerningthe most frequent


principaldiagnosesassociated
with ambulatory


visits to obstetrician-gynecologists
 presented


intable5.The diagnostic
dataaregroupedinto


classes
accordingto the Eighth Revision hzternational Classification of Diseases, Adapted for 

Use in the .United States (lCDA).Among alldiagnosesrenderedby obstetrician-gynecologists, 

Table 5. Number and percent of office visits to obstetrician-gynecologist%by the most 

frequent diagnoses rendered by the physician: United States, 1975 

[Diagnoses and code nu-mbers are basedon the Eigltth Reuision International Ckzw~ication of Diseases, .4d.pted for Use in the 

‘united States (ICDA)], 

Number of Percent
 Principal diagnoses most frequently rendered visits in of
 by the physician and ICDA code thousands visitsl


Infectiveand parasitic diseases-------------------------OOl-l36 1.805 3.8 

Moniliasis-------------------------------------------------ll2 ’882 1.8 

Neoplasms------------------------------------------------l4O-239 1,548 

Endocrine, nutritional,and metabolic diseases-----------24O-279 1,145 ::: 

Diseases of genitourinarysystem-------------------------58O-629 8.990 18.7 

Infectivediseases of cervix uteri-------------------------62O ’647 1.3 

Other diseases of cervix-----------------------------------62l 570 1.2 

Infectivediseases of uterus (except cervix), vagina, and 

mlva-----------------------------------------------------622 1,577 

Disorders of menstruation----------------------------------626 1,995 ::; 

Menopausal spptoms----------------------------------------627 853 

Symptoms and ill-definedconditions----------------------780-796 3,008 ::: 

Observation,without need for further medical care---------793 2,130 

Special conditions and examinationswithout sickness-----Y13-Yl3 27.459 5%:


Medical or special examination-----------------------------YOO 6;447 13.4


Prenatal care (normal pregnancy)---------------------------Yo6 15,119 31.4


Postpartum observation-------------------------------------YOU 1.643 3.4


Other person without complaint or illness------------------YO9 ’995 2.1


Medical and surgical aftercare-----------------------------YIN 2,596 5.4


lBasedon a total of 48,076,000 office visits.

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over 60 percent were associated with the ICDA 

classifications “special conditions and examinations without sickness” and “symptoms and il1-

defined conditions. ” Obstetrician-gynecologists 

exceeded all other physician specialties in the 

proportion of visits for “specialconditions~d 

examinations without sickness. ” (Prenatal care 

accounted for over half of the diagnoses associated with this diagnostic class. ) Visits for diseases of the genitourinary system accounted for 

an additional 19 percent of total office visits. 

Of all office visits made during 1975 for prenatal and postnatal care, approximately 70 percent were to the offices of obstetriciangynecologists and another 26 percent to the 

offices of general and family practitioners. Of all 

ambulatory visits for family pkmning, about 62 

percent were to obstetrician-gynecologists and 

28 percent to general and family practitioners. 

The diagnostic and therapeutic services provided by obstetrician-gynecologists are shown in 

table 6. Among the diagnostic services provided, 

obstetrician-gynecologists exceeded all physicians in the proportion of visits involving clinical 

lab tests, general histories and examinations, and 

blood pressure checks, but they fell below the 

overalI average in the proportion of visits for 

X-rays. Among the therapeutic services provided, obstetrician-gynecologists felI below the 

average for alI physicians in the proportion of 

drugs prescribed, office surgeries performed, and 

injections. 

Duration of visit is the time spent by the 

patient in face-to-face contact with the physic i an. The average encounter time between 

obstetrician-gynecologists and their patients was 

about 13 minutes. 

Finally, data on disposition of visits (table 6) 

Table 6. Number and percent distribution of office visits to obstetric ian-gynecolo ­

gists, by diagnostic and therapeutic services ordered or provided and disposition of � 

visit: United States, 1975


—. 

Selected diagnostic and therapeutic services ordered


or provided and dispositio~ of visit


Diagnostic and therapeutic services


Diagnostic services !


Blood pressure check


Limited history and examination


Clinical lab test


General history and examination


X-ray


Therapeutic services:


Drug prescribed


Medical counseling


Office surgery


Injection


No diagnostic or therapeutic service


Disposition of visit


No followup planned


Return at specified time


Return if needed


Admit to hospital


Telephone followup planned


Referred to other physician or agency


Number of


visits in Percent’


thousands


27,596 57.4


25;991 54.1


25,199 52.4


12,194 2:.;


850 .


17,109 35.6 

5,535 11.5 

1.458 3.0 

1;088 2.3 

1,481 3.1 

3,512


3:,;::


1;552


1,184


776


lPercents may total more than 100.0 since more than one diagnostic or therapeutic Q


service and more than one disposition could be given at a single visit.

acklncedata 5 

show that followup care of some type was physicians (59 percent). Further, the tendency


advised at 91 percent of the visits. Visits at to admit the patient to the hospital (3 percent)


which the obstetrician-gynecologist advised the slightly exceeded this disposition for zdl physi­


patient to return at a specified time (76 percent) cians (2 percent).


significantly exceeded the proportion for aIl


TECHNICAL NOTES 

SOURCE OF DATA: Data presented in this report were obtained during 1975 through the 

Nat io nal Ambulatory Medical Care Survey 

(NAMCS). The target population of NAMCS encompasses office visits within the coterminous 

United States made by ambulatory patients to 

physicians who are principally engaged in office 

practice. 

SAMPLE DESIGN: The 1975 NAMCS utilized a 

multistage probability design that involved samples of primary sampling units (PSU’S), physician practices within PSU’S, and patient visits 

within practices. Within the 87 PSU’S composing 

the first stage of selection, a sample of approximately 3,500 physicians was selected from master files maintained by the American Medical 

Association and the American Osteopathic Association, Sampled physicians, randomly assigned 

to 1 of the 52 weeks in the survey year, were 

requested to complete Patient Records (brief encounter forms) for a systematic random sample 

of office visits taking place within their practice 

during the assigned reporting period. (A facsimile of the Patient Record used is shown in a 

previous issue of Advance Data From Vital and 

Health Statistics, No. 12, October 12, 1977.) 

Additional data concerning physician practice 

characteristics such as primary specialty and 

type of practice were obtained during an induction interview. 

A complete description of the survey’s background and development has been presented in 

an earlier publication in Series 2 of Vital and 

Health Statistics (No. 61. DHEW Pub. No. 

(HRA) 76-1335. Health Resources Administration. Washington. U.S. Government Printing 

Office, Apr. 1974). A detailed description of the 

1975 NAMCS design and procedures will be 

presented in future publications. 

SAMPLING ERRORS: Since the estimates for 

this report are based on a sample rather than the 

entire universe, they are subject to sampling variability. The standard error is primarily a measure 

of sampling variability. The relative standard error of an estimate is obtained by dividing the 

standard error of the estimate by the estimate 

itself and is expressed as a percent of the estimate. Relative standard errors of selected aggregate statistics are shown in table I. The standard 

errors appropriate for the estimated percentages 

of office visits are shown in table II. 

Table 1. Approximate relative standard errors of estimated numbers of office visits 

Estimate Reletive standard 

in error in 

thousends percentage points 

500 .......................................... 

1,000 ....................................... 

2,000 ....................................... 

5,000 ....................................... 

10,000 ..................................... 

30,000 ..................................... 

100,000 ................................... 

550,000 ................................... 

30.1 

21.4 

15.3 

10.0 

7.5 

5.1 

4.0 

3.5 

Example of use of table: i% aggregate of 80,000,000 haa a 

relative standard error of 4.3 percent or a standard error of 

3,440,000 (4.3 percent of S0,000,000). 

Table 11. Approximate standard errors of percentages fOr estimated numbers of office visits 

Base of percentage 

Estimated percentage 

(number of visits 

1 or 5 or 30 or in thousands) 50 99 95 70 

1 

1,000 ..................... 2.1 4.6 6.3 8.5 9.7 10.6 

3,000 ..................... 1.2 2.7 3.7 4.9 5.6 6.1 

5,000 ..................... 0.9 2.1 2.8 3.8 4.3 4.7 

10,000 ................... 0.7 1.5 2.0 2.7 3.1 3.3 

50,000 ................... 0.3 0.7 0.9 1.2 1.4 1.5 

100,000 ................. 0.2 0.5 0.6 0.8 1.0 1.1 

500,000 ................. 0.1 0.2 0.3 0.4 0.4 0.5 

Example of use of table: An estimate of 30 percent based on 

an aggregate of 75,000,000 has a standard error of 1.2 percent. 

The relative standard error of 30 percent is 4.0 percent (1.2 percent+30 percent). 
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6 admncedata 

ROUNDING: Aggregate estimates of office visits 

presented in the tables are rounded to the nearest thousand. The rates and percents, however, 

were calculated on the basis of ori~nal, unrounded figures. Due to rounding of percents, 

the sum of percentages may not equal 100.0 percent. 

DEFINITIONS: An ambulatory patient is an individual presenting himself for personal health 

services who is neither bedridden nor currently 

admitted to any health care institution on the 

premises. 

An office is a place that the physician identifies as a location for his ambulatory practice. 

Responsibility over time for patient care and 

professional services rendered there generally resides with the individual physician rather than 

an institution. 

A visit is a direct personal exchange between 

an ambulatory patien~ and a physicia~ or a staff 

member working under the physician’s supervision for the purpose of seeking care and 

rendering health services. 

A physician is a duly licensed doctor of medicine (M. D.) or doctor of osteopathy (D. O.) currently in practice who spends time in caring for 

ambulatory patients at an office location. Excluded from NAMCS are physicians who specialize in anesthesiology, pathology, radiology; 

physicians who are federally employed; physicians who treat only institutionalized patients; 

physicians employed fudl time by an institution; 

and physicians who spend no time seeing ambulatory patients. 

SYMBOLS 

Data not available-----------–---------——-----

Category not applicable . . . 

Quantity zero ------------------------------------- -

Quantity more than Obut less than 0.05---- 0.0 

Figure does not meet standards of * reliability or precision 
Recent Issues of Advance Data From Vital and Health Statistics 

No. 19.	 Exercise and Participation in Sports Among No. 16. OffIce Viits to Internists: National AmbtdaPersons 20 Years of &e and Over: United tory Medical Care Survey, United States, 1975 

States, 1975 (In preparation) (Issued: February 7, 1978) 

No. 18. Episodes of Persons Injured: United States, No. 15. National Ambulatory Medical Care Survey of 

1975 (Issued: March 7, 1978) Wits to General and Family Practitioners, 

January-December 1975 (Issued: December 

No. 17.	 Access to Ambulatory Health Care: United 14, 1977) 

States, 1974 (Issued: February 23, 1978) 

A complete liit of Advance Data From Vital and Health Statistics is a%ailable from the Scientific and Technical 

Information Branch. 

\