EFFECT OF PREGNANCY AND ZIDOVUDINE THERAPY ON VIRAL LOAD IN HIV-1-INFECTED WOMEN

The objective of this study was to determine the effect of pregnancy a nd zidovudine (ZDV) on viral load in HIV-1 infected women. A prospecti ve nonrandomized cohort study was conducted at a university medical ce nter and affiliated clinic and included 44 HIV-1-seroposirive pregnant women seen between June 1991 and September 1995. Twenty-three women i nitiated ZDV therapy during their pregnancy. Seventeen women did not t ake antiretrovirals, and four women took ZDV prior to and throughout p regnancy. HIV-1 viral load as determined by quantitative peripheral bl ood mononuclear cell (PBMC) culture and quantitative plasma RNA levels was measured at various times during pregnancy and in the postpartum period. HIV-1 load, by both infectivity and RNA levels, was relatively low and remained stable during pregnancy and through 6 weeks post par tum. Initiation of ZDV therapy during pregnancy did not result in a si gnificant decrease in viral load at delivery when controlling for the effect of pregnancy. In those women who received ZDV therapy only duri ng pregnancy, there was a trend toward an increase in viral load measu red by PBMC infectivity 6 months post partum compared with the levels before the initiation of ZDV. Mother-to-child transmission of HIV-1 oc curred in one of 27(4%) ZDV-treated women and in two of 16 (12.5%) unt reated women. Among HIV-l-infected pregnant women with low viral level s, HIV-1 plasma RNA and infectivity remained stable during and after g estation, Although these results are based on a relatively small numbe r of women and should be considered preliminary, the lack of significa nt ZDV-associated diminution in viral levels suggests that the protect ive effect of ZDV on the mother to-child transmission of HIV-1 may not be due to the reduction in maternal viral levels but, by inference, m ay be due to the prevention of HIV-1 reverse transcription in the newb orn.