LAUSR

Introduction Women in regions with high HIV prevalence are at high risk of HIV acquisition during pregnancy and postpartum, and acute maternal HIV contributes a substantial proportion of infant HIV infections. Pre-exposure prophylaxis (PrEP) could prevent HIV during pregnancy/postpartum; however, identifying women who would most benefit from PrEP in this period is challenging. Women may not perceive risk, may not know partner HIV status and partners may have external partners during this period. PrEP offer in pregnancy could be universal or risk guided. Methods and analysis The PrEP Implementation for Mothers in Antenatal Care (PrIMA) study is a cluster randomised trial that aims to determine the best model for PrEP implementation in pregnancy, among women attending public sector maternal child health clinics in Western Kenya (HIV prevalence >25%). Twenty clinics are randomised to either universal PrEP offer following standardised counselling (‘Universal arm’ 10 clinics) or risk screening with partner self-test option (‘Targeted arm’ 10 clinics). Four thousand women will be enrolled and followed through 9-month postpartum. The primary analysis will be intention to treat. Outcomes reflect the balance between HIV preventive effectiveness and avoiding unnecessary PrEP exposure to women at low risk and include: maternal HIV incidence, PrEP uptake, PrEP adherence, PrEP duration, ‘appropriate’ PrEP use (among women with objective evidence of potential risk), infant birth outcomes, infant growth and partner self-testing uptake. To better understand the feasibility and acceptability of the provision of PrEP in these settings, qualitative interviews and cost-effectiveness analyses will be conducted. Ethics and dissemination The protocol was approved by the institutional review boards at Kenyatta National Hospital and the University of Washington. An external advisory panel monitors adverse and social harm events. Results will be disseminated through peer-reviewed journals, presentations at local and international conferences to national and global policy makers, community and participants. Trial registration number NCT03070600.