UCLA

HIV acquisition risks remain high for pregnant and breastfeeding populations in South Africa. Oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate/emtricitabine (TDF-FTC) can be used daily during periods of sexual activity to prevent HIV infections for cisgender women. In 2021, oral PrEP became the standard of care for HIV prevention during pregnancy and breastfeeding periods. The objective of this dissertation was to evaluate trends in oral PrEP initiation, continuation, and adherence among adolescent girls and young women, women experiencing intimate partner violence, and by sexual behaviors throughout gestational periods and postpartum. We used data from the PrEP in Pregnancy and Postpartum (PrEP-PP) study, a prospective cohort in Cape Town of 1200 participants without HIV. The PrEP-PP study provided HIV prevention counselling and offered PrEP to pregnant and breastfeeding women.The first study evaluated the oral PrEP cascade framework among adolescent girls and young women (AGYW) in the PrEP-PP study. Approximately 83% of AGYW initiated PrEP at their first antenatal care (ANC) visit, 34% continued PrEP at 6 months, and 11% stopped and restarted. AGYW with a higher HIV risk had an increased adjusted likelihood of continuing PrEP through 6 months (adjusted odds ratio[aOR]:1.91 [95% CI, 1.15-3.16]). About 7% of AGYW had high adherence to PrEP at 6 months. The second study examined the relationship between recent and past-year intimate partner violence (IPV) experienced by pregnant and postpartum women and oral PrEP continuation and adherence. Women who experienced past-year IPV were less likely to discontinue PrEP(adjusted hazards ratio: 0.80 (95% CI: 0.61, 1.06) and had higher adherence(quantifiable tenofovir-diphosphate[TFV-DP] in dried blood spots; aOR=1.82 (95% CI: 1.02, 3.25) at 6-month follow-up visits. The third study evaluated prevention-effective adherence by gestational trimesters of pregnancy and postpartum. Prevention-effective adherence(initiation/quantifiable TFV-DP or reported use during follow-up among those engaging in condomless sex) was 65% overall, with the highest adherence in trimester 1(81%) and lowest at early postpartum(49%). There was a positive association between engaging in condomless sex and PrEP use(quantifiable TFV-DP or self-reported use; adjusted risk ratio:1.88; 95% CI: 1.67, 2.12). In conclusion, AGYW during pregnancy and postpartum had high oral uptake, but retention in PrEP by 6 months was low. Those with higher HIV risks are more likely to continue PrEP. Pregnant/postpartum women who experienced past-year IPV were more likely to stay in the study and had greater adherence. The findings suggest that pregnant and postpartum women align their PrEP use with their potential HIV risks. Implementing violence screening and oral PrEP counselling (with conversations about changing HIV risks) at ANC may improve HIV prevention for women during pregnancy and postpartum in South Africa and beyond.