Zidovudine prophylaxis is recommended to reduce perinatal HIV-1 transmission, but there are limited data on long-term effects on women's health. Pediatrics AIDS Clinical Trials Group (PACTG) 288 was a prospective observational study among US women randomized to zidovudine or placebo in PACTG 076 that was designed to evaluate and compare postpartum clinical, immune, and viral parameters between randomized treatment arms. Forty-eight percent (226/474) of eligible women enrolled in the study (mean follow-up of 4.1 years). Progression and time to AIDS or death were similar in both groups, observed in 21 (19%) zidovudine group women and 29 (25%) placebo group women (RR = 0.73, 90% CI: 0.46-1.17). No significant differences in CD4(+) lymphocyte count or HIV RNA levels were detected. Genotypic zidovudine resistance was detected in 10% of 156 women (9% of zidovudine group women and 11% of placebo group women). Based on our data, ZDV monotherapy could be considered as chemoprophylaxis to reduce perinatal HIV transmission for minimally symptomatic HIV-infected pregnant women with a low viral load and normal CD4(+) cell count who do not want to receive highly active antiretroviral therapy because of concern about potential side effects or who wish to reduce fetal exposure to multiple drugs during pregnancy.

OBJECTIVE:To identify modifiable obstetric factors associated with the failure of zidovudine chemoprophylaxis to prevent perinatal human immunodeficiency virus type 1 (HIV-1) transmission.METHODS:We analyzed data from Pediatric AIDS Clinical Trials Group protocol 076, a randomized, double-masked, placebo-controlled trial that demonstrated that a zidovudine regimen could prevent perinatal HIV-1 transmission. We estimated the zidovudine treatment effect using the relative reduction in transmission risk among women randomized to treatment with zidovudine compared with women randomized to receive placebo. Univariate and multivariate statistical analyses were used to assess whether the treatment effect differed in magnitude according to potential antepartum or intrapartum risk factors.RESULTS:In the univariate analysis, the zidovudine treatment effect was found to differ significantly in magnitude according to quartile of maternal weight at the time of study entry (interaction test, P = .03); among women in the heaviest-weight quartile (weight more than 82 kg), there was a 26% relative reduction in transmission risk, compared with a 79% relative reduction among the other three quartiles (interaction test, P = .05). In the zidovudine treatment group, women who transmitted HIV-1 were significantly more likely than nontransmitters to have had antepartum procedures or conditions associated with increased risk of fetal exposure to maternal blood or cervicovaginal secretions (43% compared with 19%, P = .04). In the multivariate analysis, adjustment for the plasma HIV-1 RNA level and CD4+ cell percentage did not eliminate the differential treatment effect according to these factors.CONCLUSION:High maternal weight and conditions associated with fetal exposure to maternal blood or cervicovaginal secretions may diminish the efficacy of zidovudine chemoprophylaxis.

Objective: To identify modifiable obstetric factors associated with the failure of zidovudine chemoprophylaxis to prevent perinatal human immunodeficiency virus type 1 (HIV-1) transmission.Methods: We analyzed data from Pediatric AIDS Clinical Trials Group protocol 076, a randomized, double-masked, placebo-controlled trial that demonstrated that a zidovudine regimen could prevent perinatal HIV-1 transmission. We estimated the zidovudine treatment effect using the relative reduction in transmission risk among women randomized to treatment with zidovudine compared with women randomized to receive placebo. Univariate and multivariate statistical analyses were used to assess whether the treatment effect differed in magnitude according to potential antepartum or intrapartum risk factors.Results: In the univariate analysis, the zidovudine treatment effect was found to differ significantly in magnitude according to quartile of maternal weight at the time of study entry (interaction test, P = .03); among women in the heaviest-weight quartile (weight more than 82 kg), there was a 26% relative reduction in transmission risk, compared with a 79% relative reduction among the other three quartiles (interaction test, P = .05). In the zidovudine treatment group, women who transmitted HIV-1 were significantly more likely than nontransmitters to have had antepartum procedures or conditions associated with increased risk of fetal exposure to maternal blood or cervicovaginal secretions (43% compared with 19%, P = .04). In the multivariate analysis, adjustment for the plasma HIV-1 RNA level and CD4(+) cell percentage did not eliminate the differential treatment effect according to these factors.Conclusion: High maternal weight and conditions associated with fetal exposure to maternal blood or cervicovaginal secretions may diminish the efficacy of zidovudine chemoprophylaxis. (Obstet Gynecol 1999;94:897-908. (C) 1999 by The American College of Obstetricians and Gynecologists.).

Objective:To determine the safety of the zidovudine (ZDV) regimen utilized in the Pediatric AIDS Clinical Trial Group (ACTG) 076 study. Design:ACTG 076 was a randomized, double-blind, placebo-controlled trial which demonstrated that a ZDV regimen could prevent mother-to-child HIV-1 transmission. Infants were followed through 18 months of age and women were followed through 6 months postpartum. Methods:Maternal complications, pregnancy outcomes, growth and development of the uninfected infants, and HIV-1 disease progression in the women were monitored prospectively. Results:Maternal therapy was well tolerated. There was no serious pattern of adverse pregnancy outcomes associated with ZDV use. Amongst the ZDV-exposed infants, the only recognized toxicity was anemia within the first 6 weeks of life; the risk for anemia was not associated with premature delivery, duration of maternal treatment, degree of maternal immunosuppression, or maternal anemia. ZDV treatment was not associated with an increased incidence of newborn structural abnormalities. At 18 months of age, uninfected infants did not differ in growth parameters or immune function. No childhood neoplasias were reported in either group. In the women, at 6 months postpartum, there were no differences in clinical, immunologic, or virologic disease progression. Conclusion:There were no identified problems that would alter current recommendations for the routine use of ZDV for the prevention of mother–child HIV-1 transmission.