Background: Women who plan to conceive while exposed to HIV need strategies to mitigate HIV acquisition risks. We are conducting a longitudinal study in Durban, South Africa to evaluate use of TDF/FTC as PrEP among HIV-exposed women planning for pregnancy.
Methods: We enroll HIV-uninfected women aged 18-35 years with personal or partner plans for pregnancy in the next year, not using long-acting contraception, and with a stable partner living with HIV or of unknown-serostatus. Safer conception counseling occurs at each post-enrollment study visit and PrEP is offered along with quarterly adherence counseling. We follow women for one year; those who become pregnant are followed through pregnancy. The primary objective is to evaluate periconception and pregnancy PrEP uptake and adherence. Adherence is defined as the number of electronic pill cap openings divided by number of days of expected PrEP use. Women provide blood for plasma tenofovir levels quarterly. We present data for the first 147 participants including adherence data for the first 52 participants completing 3-month follow-up.
Results: Between October 2017 and December 2018 we enrolled 147 women with median age 24 (range 18-35) years and 146 (99%) identifying as black South African. Partner HIV-serostatus was unknown by 96%. Among 135 women completing safer conception counseling, nearly two-thirds (N=86) chose to initiate PrEP. At the time of analysis, 52 had completed the 3-month follow-up visit with adherence data. During these first months, mean weekly adherence was 71% (95% CI: 66-77%). Nearly 50% of participants achieved >80% adherence; 37% had 50-80% adherence, and 15% averaged < 50% adherence to daily PrEP. Among 40 PrEP-initiators providing plasma at the 3-month visit, 45% had detectable tenofovir; 38% had levels associated with daily dosing (>40ng/mL).
Conclusions: Among women at-risk for HIV acquisition, and planning for pregnancy, most choose PrEP as a safer conception strategy. Adherence is high with nearly one-half with detectable tenofovir. Ongoing mixed-methods analysis will explore how to refine adherence support to optimize adherence for those women who want, but struggle, to use PrEP to safely achieve reproductive goals. These data indicate high demand for and acceptability of periconception PrEP in South Africa.