Introduction: Pre-exposure prophylaxis (PrEP) may be an important safer conception strategy for HIV-1–uninfected women with HIV-1–infected partners. Understanding medication adherence in this population may inform whether PrEP is a feasible safer conception strategy.
Methods: We evaluated predictors of pregnancy and adherence to study medication among HIV-1–uninfected women enrolled in a randomized placebo-controlled trial of PrEP among African HIV-1–serodiscordant couples. Participants were counseled on HIV-1 risk reduction, contraception, and adherence and tested for pregnancy at monthly study visits. Pill counts of dispensed drug were performed and, at a subset of visits, plasma was collected to measure active drug concentration.
Results: Among 1785 women, pregnancy incidence was 10.2 per 100 person-years. Younger age, not using contraception, having an additional sexual partner, and reporting unprotected sex were associated with increased likelihood of pregnancy. Monthly clinic pill counts estimated that women experiencing pregnancy took 97% of prescribed doses overall, with at least 80% pill adherence for 98% of study months, and no difference in adherence in the periconception period compared with previous periods (P = 0.98). Tenofovir was detected in plasma at 71% of visits where pregnancy was discovered. By multiple measures, adherence was similar for women experiencing and not experiencing pregnancy (P ≥ 0.1).
Conclusions: In this clinical trial of PrEP, pregnancy incidence was 10% per year despite excellent access to effective contraception. Women experiencing pregnancy had high medication adherence, suggesting that PrEP may be an acceptable and feasible safer conception strategy for HIV-1–uninfected women with HIV-1–serodiscordant partners.
*Division of Infectious Disease and Center for Global Health, Massachusetts General Hospital, Boston, MA;
†Division of Infectious Disease, Beth Israel Deaconess Medical Center, Boston, MA;
‡Department of Global Health, University of Washington, Seattle, WA;
§Kenya Medical Research Institute, Nairobi, Kenya;
‖Department of Obstetrics, Gynecology and Reproductive Sciences, Bixby Center for Global Reproductive Health, University of California San Francisco, San Francisco, CA;
¶Department of Medicine, Johns Hopkins University, Baltimore, MD;
#Department of Medicine, University of Washington, Seattle, WA; and
**Department of Epidemiology, University of Washington, Seattle, WA.
Correspondence to: Lynn T. Matthews, MD, MPH, Center for Global Health, Massachusetts General Hospital, 100 Cambridge Street, 15th Floor, Boston MA, 02114. (e-mail: firstname.lastname@example.org).
The Partners PrEP study was supported by research grant (OOP47674) from the Bill & Melinda Gates Foundation; Gilead Sciences provided medication. This analysis was also supported by the National Institute of Mental Health and the Eunice Kennedy Shriver National Institute of Child Health and Development of the National Institutes of Health under award numbers K23MH095655, K24MH87227, R21HD074439, K99HD076679, and R01MH095507.
C.H. has a contract with Gilead Sciences for partial support of a clinical study managed by Johns Hopkins University. The remaining authors have no conflicts of interest to disclose.
The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Members of the Partners PrEP Study Team are listed in Appendix.
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Received May 23, 2014
Accepted May 23, 2014