Objective: To determine whether zidovudine, administered to reduce vertical transmission of human immunodeficiency virus type 1 (HIV-1), impacts the level of maternal viral DNA within the lymphocytes of infected pregnant women.
Study design: A prospective, nonrandomized study of 42 HIV-1 infected pregnant women. Nineteen women received zidovudine therapy to reduce HIV-1 perinatal transmission, and 23 were untreated. HIV-1 DNA was determined by polymerase chain reaction amplification of lymphocyte DNA from maternal blood samples obtained at the time of delivery. Treated and untreated, transmitting and nontransmitting groups were compared for clinical, virologic, and immunologic parameters with at test or a Fisher Exact Test, and for copies of HIV-1 DNA per 10(6) CD4+ T cells with a Mann-Whitney rank sum test.
Results: Untreated pregnant women who transmitted HIV-1 to their infants had tower CD4+ T-cell counts and a greater degree of immune complex dissociated p24 antigenemia than did the untreated nontransmitting group (p < 0.01) but did not differ significantly with respect to age, race, or mode of delivery. The level of HIV-1 proviral DNA within lymphocytes was significantly greater in the untreated transmitting group than in the nontransmitting mothers (p = 0.003). Zidovudine treatment resulted in a 78% decrease in maternal transmission (p = 0.017). However, there was not a significant difference in DNA copy numbers in CD4+ T cells in the treated compared with the untreated groups.
Conclusion: Zidovudine reduces HIV-1 maternal transmission independent of its effect on the level of the maternal peripheral blood proviral load.