Evaluating the Pharmacokinetics, Feasibility, Acceptability, and Safety of Oral Pre-Exposure Prophylaxis for HIV Prevention During Pregnancy and Postpartum

PK Component (Groups 1 and 2) Inclusion Criteria: * At study entry, pregnant or recently delivered, in one of the following two enrollment windows: * Group 1: Gestational age of 14 to 24 weeks. * Group 2: 6 to 12 weeks postpartum. * Willing to initiate daily PrEP for 12 weeks under directly observed therapy. * HIV and Hepatitis B negative. * At screening: * Grade 1 or normal alanine transaminase (ALT), hemoglobin (HB), absolute neutrophil count (ANC) and normal creatinine clearance (CrCl). * Negative or trace proteinuria (less than Grade 1). * Normal dipstick urine for glucose (less than Grade 1). * Mother weighs greater than 35 kg. * Intention to stay within the study site's catchment area for at least 12 weeks (or through delivery). Exclusion Criteria (PK Component and PrEP Comparison Component): * Any current significant uncontrolled, active or chronic disease process. * History of any of the following: * Sickle cell anemia, chronic bleeding, blood transfusion within the past 120 days or other blood dyscrasias * Bone fracture not explained by trauma * Allergy/sensitivity to FTC/TDF or its components * Fetus has a known or suspected major congenital anomaly * Mother has confirmed renal insufficiency, a history of renal parenchymal disease or single kidney * Current use of prohibited medications listed in the protocol * Concurrent participation in any biomedical HIV prevention or investigational drug in an HIV vaccine or microbicide study * Past parti…