Pharmacokinetic Study of Long-acting Antiretrovirals and Contraceptives in HIV

This study is being done to understand how long-acting injectable cabotegravir (CAB-LA) used for HIV pre-exposure prophylaxis (PrEP) and hormonal contraceptive methods affect each other when used at the same time. Women who are already using CAB-LA or not using PrEP will choose to join one of several groups based on whether they use injectable contraceptive (IM DMPA), an etonogestrel implant, or no hormonal contraceptive. Participants will have study visits every 4 to 12 weeks for up to 12 or 24 weeks after starting a contraceptive method to collect blood samples and measure levels of CAB-LA and hormone concentrations. The study will compare these levels to see if taking CAB-LA changes hormone concentrations or if using hormonal contraception changes CAB-LA drug levels. Safety, side effects, satisfaction, and continuation of CAB-LA PrEP and contraceptive methods will also be evaluated.