Prenatal zidovudine use and congenital anomalies in a medicaid population

Objectives: To examine the association of prescribed zidovudine (ZDV) during pregnancy with congenital anomalies in a population-based cohort. Methods: Medicaid claims were used to assess prescribed ZDV and children's major congenital anomalies in 1932 liveborn deliveries from 1993 to 1996 to HIV-infected women in the state of New York (NYS), U.S.A.. Prevalence of anomalies in the cohort was compared with that of a general NYS population. Within the cohort, adjusted odds of any anomaly were compared by receipt of ZDV and by trimester of first prescription. Results: The adjusted prevalence of any anomaly in the study cohort was 2.76 times greater than in the general population (95% confidence interval [CI], 2.36-3.17). Children of study women who were prescribed ZDV had increased adjusted odds of any anomaly (adjusted odds ratio [OR], 1.55; 95% CI, 1.01-2.29). Adjusted ORs (with CIs) by trimester of first prescription were 1.20 (0.58-2.51), 1.47 (0.85-2.55), and 1.84 (1.04-3.25) for the first, second, and third trimesters, respectively. Conclusion: Children of HIV-infected women in this cohort had a greater prevalence of major anomalies than did the general NYS population. An increased risk of major anomalies was not evident for first trimester exposure when the association would have been most biologically plausible.