The reporting of pre-existing maternal medical conditions and complications of pregnancy on birth certificates and in hospital discharge data

Objective

The purpose of this study was to determine the accuracy of live-birth certificates and hospital discharge data that reported of pre-existing maternal medical conditions and complications of pregnancy.

Study design

We conducted a population-based validation study in 19 non-federal short-stay hospitals in Washington state with a stratified random sample of 4541 women who had live births between January 1, 2000, and December 31, 2000. True- and false-positive fractions were calculated.

Results

Birth certificate and hospital discharge data combined had substantially higher true-positive fractions than did birth certificate data alone for cardiac disease (54% vs 29%), acute or chronic lung disease (24% vs 10%), gestational diabetes mellitus (93% vs 64%), established diabetes mellitus (97% vs 52%), active genital herpes (77% vs 38%), chronic hypertension (70% vs 47%), pregnancy-induced hypertension (74% vs 49%), renal disease (13% vs 2%), and placenta previa (70% vs 33%). For the 2 medical risk factors that are available only on birth certificates, true-positive fractions were 37% for established genital herpes and 68% for being seropositive for hepatitis B surface antigen.

Conclusion

In Washington, most medical conditions and complications of pregnancy that affect mothers are substantially underreported on birth certificates, but hospital discharge data are accurate in the reporting of gestational and established diabetes mellitus and placenta previa. Together, birth certificate and hospital discharge data are much superior to birth certificates alone in the reporting of gestational diabetes mellitus, active genital herpes, and chronic hypertension.

Key words: Pregnancy complication, Live birth, Birth certificate, International Classification of Diseases, Ninth Revision, code