Early pre-exposure prophylaxis (PrEP) discontinuation among pregnant and postpartum women: Implications for maternal PrEP roll out in South Africa

Introduction: Oral pre-exposure prophylaxis (PrEP) is a safe and effective prevention strategy to reduce risk of HIV in pregnancy and postpartum. Effective PrEP requires daily PrEP adherence, but little is known about maternal PrEP continuation and risk factors that influence optimal PrEP use. Methods: The PrEP in pregnancy and postpartum (PrEP-PP) study is an ongoing cohort study that enrolled consenting pregnant, HIV-uninfected women at first antenatal care (ANC) visit, followed through 12-months postpartum. HIV-uninfected women and girls >16-years who were eligible for the study received HIV prevention counseling and were offered PrEP. Interviewers collected socio-demographic, behavioral data from participants at each visit. We analyzed the proportion of women who initiated PrEP and the proportion who continued on PrEP after 3-months with associated correlates, including side effects whilst on PrEP, by estimating the prevalence ratio (95% CI) adjusting for a priori confounders. Results: Between August 2019 and February 2021, we enrolled 891 pregnant women (median gestation=21wks; age=26yrs). Following PrEP counseling, 90% of women initiated PrEP at their first ANC visit (n=801); 60% were married or cohabiting. Three-quarters of women on PrEP returned for a repeat prescription at 1-month; 62% returned at 3-months. One-third of women on PrEP reported a side effect, mostly nausea/vomiting, dizziness, and headache. Women on PrEP in the 1st or 2nd trimester had higher odds of reporting side effects (aOR=2.61; 95%CI=1.17-5.84) vs. postpartum women. Women who reported side effects continued with PrEP less than those who did not report side effects (aPR=0.88; 95% CI=0.78-0.99) adjusting for covariates. Women who had >1 previous pregnancy (aPR=0.76;95%CI=0.59-1.00) or were postpartum (aPR=0.86;95%CI=0.75-0.99) continued less than women who were primigravid or pregnant. Women who reported having an HIV+ partner (aPR= 1.70;95% CI=1.55-1.86) or unknown partner serostatus (aPR=1.14;95%CI=1.01-1.29) were more likely to continue on PrEP than those who had HIV-negative partners. Conclusion: PrEP initiation and early continuation were high in ANC in this setting. Being postpartum and experiencing side effects were associated with lower PrEP continuation, presenting an opportunity for improved clinical management and counseling during pregnancy of nausea/vomiting to address early, transient side effects. Interventions for postpartum women on PrEP are urgently needed.