Initiation and continued use of oral pre-exposure prophylaxis among pregnant and postpartum women in South Africa (PrEP-PP): a demonstration cohort study

Background: When used effectively, oral pre-exposure prophylaxis (PrEP; tenofovir disoproxil fumarate and emtricitabine) prevents maternal HIV acquisition and reduces the risk of vertical transmission. Our study aimed to better understand PrEP initiation, continued use, and adherence in pregnant and postpartum women.

Methods: The PrEP in Pregnancy and Postpartum (PrEP-PP) study is a demonstration cohort study that enrolled pregnant women aged 16 years and older without HIV attending their first antenatal care visit in Cape Town, South Africa, between Aug 29, 2019, and Oct 10, 2021. Eligible, consenting women were followed up quarterly up to 12 months postpartum with regular HIV testing and offer of PrEP with ongoing adherence counselling. The primary outcome was distribution of women across the PrEP cascade (ie, initiation and continuation up to 12 months postpartum) with crude and adjusted hazard ratios (HRs). We also report on HIV incidence by pregnancy and postpartum status.

Findings: Overall, 1195 pregnant women were recruited and followed up (median age 26 years, IQR 23-31; median gestational age 21 weeks, IQR 15-31); 1009 (84·4%) started PrEP at enrolment. Among women who initiated PrEP at enrolment, 668 (67·5%) of 990 continued PrEP at the 1-month follow-up, 485 (49·9%) of 972 continued at 3 months, 392 (39·4%) of 994 at 6 months, and 275 (27·4%) of 1005 at 12 months. Of 186 women who did not accept PrEP at enrolment, 70 (37·6%) of 186 subsequently initiated PrEP. Overall, 200 (18·6%) of 1076 women continued PrEP at 12 months postpartum. Of 186 women who did not initiate PrEP at baseline, 70 (37·6%) subsequently initiated PrEP during the study. Factors associated with PrEP discontinuation up to 12 months postpartum included being married or cohabiting (adjusted HR 1·32, 95% CI 1·16-1·50), condomless sex since last visit (1·43, 1·23-1·65), reporting intimate partner violence (2·03, 1·59-2·59), or depression in the past 12 months (1·53, 1·14-2·05). Overall, 16 women seroconverted over 1673·8 woman-years (HIV incidence rate 0·96 per 100 woman-years, 95% CI 0·49-1·42); 14 discontinued PrEP use and two never initiated PrEP. HIV incidence was 0·28 per 100 woman-years during pregnancy (95% CI 0·22-0·33), and the incidence rate ratio was 1·77 per 100 woman-years (0·53-5·90) 0-6 months postpartum and 2·19 per 100 woman-years (0·61-7·83) 6-12 months postpartum compared with pregnant women.

Interpretation: There is an urgent need for the integration of PrEP into antenatal and postnatal care and interventions that address barriers to continued use, including targeted counselling during pregnancy and postpartum to reduce PrEP discontinuation.

Funding: National Institute of Mental Health and Fogarty International, US National Institutes of Health.

Translation: For the French translation of the abstract see Supplementary Materials section.