Birth outcomes following zidovudine exposure in pregnant women: the Antiretroviral Pregnancy Registry.

Potential risk of adverse birth outcomes associated with the use of antiretrovirals in human immunodeficiency virus (HIV)-infected women during pregnancy must be assessed. Data through June 1995 are reported from the worldwide Antiretroviral Pregnancy Registry on the incidence of structural birth defects following prenatal exposure to zidovudine. Healthcare professionals register pregnant women anonymously. Follow-up is at time of delivery. Results are reviewed semi-annually by an advisory committee, which follows the Centers for Disease Control and Prevention (CDC) guidelines for definitions of birth defects. From 1989 through to 30 June, 1995, 198 outcomes involving exposure to zidovudine were reported. Of 73 first-trimester exposures, outcomes included one infant with a birth defect. Of 125 exposures in the second and third trimesters, six infants were reported with birth defects. Data on other antiretrovirals are insufficient for analysis. The Registry findings to date do not show an increase in the number of birth defects (1/63 in the first trimester, or 1.59%, 95% CI 0.083%, 9.69%) following prenatal zidovudine exposure when compared with that expected in the general population; however, the number of outcomes to date represents a sample of insufficient size for developing precise estimates regarding the teratogenic risk of zidovudine.