Evaluation of selected characteristics of pregnancy drug registries

Given that half of U.S. pregnancies are unintended and some prescription dr ugs are frequently used by reproductive-age women, there is an increasing i nterest in establishing pregnancy registries to monitor fetal exposures and pregnancy outcomes. Physicians report prenatal exposures and pregnancy out comes, including birth defects, to these registries. We compared pooled dat a from four pregnancy registries with data from a population-based birth de fects surveillance system, the Metropolitan Atlanta Congenital Defects Prog ram (MACDP); specifically we compared the defect prevalence by organ system and severity, the number of defects per baby, and timeliness. We also comp ared the number of zidovudine exposures identified by a registry to the num ber identified by 29 states with HIV surveillance. The registries' overall defect prevalence (41/1471, 2.7%) was slightly lower than MACDP (6157/19564 2, 3.2%). The defect prevalence by organ system was Similar, except for gen itourinary defects which had a lower prevalence in the registries than in M ACDP (RR = 0.22; 95% Cl = 0.07,0.67). The prevalence of having an internal defect or severe defect reported was lower in the registries (RR = 0.75, 95 % Cl = 0.53,1.06, and RR = 0.82, 95% Cl = 0.57,1.19, respectively). The mea n number of defects identified per affected infant was 2.82 in MACDP and 1. 68 in the registries. Both systems received 69% of defect reports by 6 mont hs after birth. In similar 6-month periods, U.S. HIV surveillance identifie d 300 prenatal zidovudine exposures, while the registry received 134 worldw ide reports. If registries improve their ascertainment of defects and expos ed pregnancies, they will increase their chance of detecting signs of possi ble teratogenicity. Published 1999 Wiley-Liss, Inc.