Abstract (30 lines) The HPTN 084 OLE allows for participants to discontinue contraception and if becoming pregnant to continue active dosing with CAB LA throughout pregnancy and breastfeeding. The HPTN 084 pregnancy substudy will provide important information for prevention of HIV in people of reproductive potential, when they are often most vulnerable to HIV. In addition, the pregnancy substudy will provide valuable information about the safety and pharmacokinetics of CAB LA for pregnant and lactating people and their infants. Specifically, this substudy will contribute information about the incidence of pregnancy in a cohort of women on oral and long-acting PrEP, assess maternal safety outcomes (Serious adverse events, AEs, and weight gains), pregnancy outcomes (such as the rates of spontaneous abortion, ectopic pregnancy, low birthweight, and early or full-term births), and infant safety outcomes (SAEs, AEs, and growth). In addition, the substudy will assess pharmacokinetic parameters during the pre-pregnant, pregnant, and post-partum periods, including concentration time profiles and trough CAB concentrations. Utero/peripartum exposure will also be assessed by examining CAB concentrations in cord blood and corresponding maternal plasma. Infant exposure through breastmilk will be examining by analyzing CAB concentrations in maternal plasma, breastmilk, and infant plasma. The HPTN SDMC, housed at the Fred Hutchinson Cancer Research Center in Seattle, takes advantage of the strengths of the institution, which also includes the HVTN SDMC. The HPTN SDMC has faculty biostatisticians experienced in the design, conduct and analysis of global clinical trials and surveillance studies, who support research through leadership in statistical design, trial conduct and analysis, and development and implementation of innovative statistical methods as needed and motivated by the scientific goals. The SDMC provides regulatory compliant data management functions for all trials it implements, including electronic data capture directly from research sites or the field, integration of laboratory specimens and assay results, and electronic participant reported outcomes.