ObjectiveTo describe the safety, efficacy, and perinatal transmission rates of human immunodeficiency virus (HIV) with combination antiretroviral therapy in pregnancy.MethodsRetrospective study of all HIV-infected pregnant women treated with combination antiretroviral therapy after September 1, 1996, and who delivered by September 1, 1998, at Bronx-Lebanon Hospital Center.ResultsThirty women received combination therapy, 13 with protease inhibitor. Median baseline CD4 was 285 cells/mm3; 16 (53%) had AIDS, 20 (67%) were antiretroviral-experienced, and 11 (37%) were illicit substance users. Fourteen were receiving antiretroviral therapy (eight with protease inhibitor) during the first trimester. Combination therapy was prescribed for a median of 26 weeks during pregnancy. One third changed antiretroviral therapy, and nearly half (47%) were nonadherent. Twenty-four women had a successful viral load and/or CD4 response. The median (range) delivery gestation was 39 (32–42) weeks, and the median (range) birth weight was 2892 (1430–3863) g. Adverse outcomes included one stillbirth; one case of microcephaly; and five infants less than 2500 g, two of which were under 36 weeks' gestation. Median birth weight did not differ with maternal protease exposure. None of the 26 infants studied for at least 4 months had HIV infection. Associated maternal complications were four cases of pregnancy-induced hypertension, one of gestational diabetes, and one exacerbation of hepatitis C virus.ConclusionCombination antiretroviral therapy in pregnancy was efficacious in reducing viral load, increasing CD4, and preventing vertical HIV transmission in women with advanced HIV disease, extensive antiretroviral experience, prior history of vertical transmission, and/or substance abuse. The findings are promising in this preliminary report that combination antiretroviral therapy may not be related to major infant toxicity, but further study is warranted.