Changes in plasma HIV-1-RNA viral load and CD4 cell counts, and lack of zidovudine resistance among pregnant women receiving short-course zidovudine.

ABSTRACT

OBJECTIVE: To describe changes in HIV-1 plasma viral load (VL) and CD4 cell counts and to assess zidovudine resistance associated with a short course of oral zidovudine during late pregnancy. METHODS: From April 1996 to February 1998 in Abidjan, Côte d'Ivoire, 280 HIV-1-seropositive women were randomly assigned at 36 weeks' gestation to receive zidovudine (300 mg) or placebo twice a day, and then one tablet every 3 h from the onset of labor until delivery. Blood samples obtained every 2 weeks until delivery, then at 2 and 4 weeks, and 3 or 6 months after delivery were tested from selected women based on duration of therapy for plasma VL and CD4 cell counts, and samples from 20 women in the zidovudine group were tested by DNA sequencing for the presence of zidovudine resistance mutations. RESULTS: In the zidovudine group, the median reduction in plasma VL (log(10) copies/ml) was -0.48 after 2 weeks (P = 0.02 versus placebo), -0.48 after 4 weeks (P = 0.06), -0.80 after 6 weeks (P = 0.29) of treatment, -0.12 at delivery (P = 0.11), +0.21 at 2 weeks (P = 0.83), +0.17 at 4 weeks (P = 0.69), and +0.21 at 3 months (P = 0.56) postpartum. Median CD4 cell counts were higher in the zidovudine than in the placebo group after 2, 4, and 6 weeks of treatment (P < 0.05). No mutations associated with zidovudine resistance were identified in any of the samples tested. CONCLUSION: These findings suggest that a short course of zidovudine has no adverse HIV-1 virological consequences for the mother.