How well do birth certificates describe the pregnancies they report? The Washington State experience with low-risk pregnancies.
OBJECTIVE
Birth certificates are a major source of population-based data on maternal and perinatal health, but their value depends on the accuracy of the data. This study assesses the validity of information recorded on the birth certificates for women in Washington State who were considered to be low risk at entry into care.


METHODS
Birth certificates were matched to data abstracted from prenatal and intrapartum clinic and hospital records of a sample of 1937 Washington State obstetrical patients who were considered to be low risk at the beginning of their pregnancies. Accuracy of a variety of pregnancy characteristics (e.g., complications, procedures) on the birth certificate was analyzed using percentage agreement and sensitivity with record abstracts as the "gold standard." Next, we weighted the data from each source to produce estimates of pregnancy characteristics in the population. We compared these estimates from the two data sources to see whether they provide similar pictures of this subpopulation.


RESULTS
Missing data for specific items on the birth certificates ranged from 0% to 24%. The birth certificate accurately captured gravidity and parity, but was less likely to report prenatal and intrapartum complications. The population estimates of the two data sources were significantly different.


CONCLUSIONS
Because birth certificates significantly underestimated the complications of pregnancies, number of interventions, number of procedures, and prenatal visits, use of these data for health policy development or resource allocation should be tempered with caution.
Dobie
S A
SA
University of Washington, Department of Family Medicine, Seattle 98195-6390, USA. dob@u.washington.edu
Baldwin
L M
LM
Rosenblatt
R A
RA
Fordyce
M A
MA
Andrilla
C H
CH
Hart
L G
LG
D000328:Adult; D001719:Birth Certificates; D003625:Data Collection / Q000379:methods*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008499:Medical Records / Q000706:statistics & numerical data; D011247:Pregnancy / Q000706:statistics & numerical data*; D011248:Pregnancy Complications / Q000453:epidemiology; D011295:Prenatal Care / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D017584:Reproductive History; D014861:Washington / Q000453:epidemiology