Background: Given well documented challenges faced by pregnant women living with HIV taking lifetime ART, it is critical to understand the impact of short-term ART exposure followed by treatment interruption on maternal health outcomes.

Methods: HIV+ breastfeeding (BF) and Formula Feeding (FF) women with CD4 counts > 350 cells/mm3, enrolled in the 1077BF/1077FF PROMISE trial were followed to assess the effect of ART during pregnancy and breastfeeding respectively. The first analysis compared ART use limited to the antepartum period (AP-only) relative to women randomized to Zidovudine. The second analysis included women with no pregnancy combination ART exposure; and compared women randomized to either ART or no ART during postpartum (PP-only). Both analyses included follow-up time beyond breastfeeding period. The primary outcome was progression to AIDS and/or death. Secondary outcomes included adverse events and HIV-related events.

Results: 3490 and 1137 HIV+ women were enrolled from 14 sites in Africa and India from April 2011 through September 2014 in cohort AP-only and PP-only, respectively. Most were Black African (96%); median age was 27 years; 97% were WHO Clinical Stage I; and most had a screening CD4 count ≥500 cells/mm3 (78%). The rate of progression to AIDS and/or death was similar and low across all comparison arms (AP comparison, HR = 1.14, 95%CI (0.44, 2.96), p-value = 0.79). In the PP-only cohort, the rate of WHO stage 2-3 events was lower for women randomized to ART(HR = 0.65, 95% CI 0.42, 1.01, p-value = 0.05).

Conclusion: The incidence of AIDS and/or death was low in pregnant/postpartum HIV+ women with highCD4 cell counts for all comparison arms. This provides some reassurance that there were limited consequences for short term ART interruption in this group of asymptomatic HIV+ women during up to 4 years of follow up; and underscores that even short term ART exposure postpartum may reduce the risk of WHO grade 2-3 disease progression.