This study looks at how certain birth control methods might change a woman's immune system and affect her risk of getting HIV, a virus that affects the body's ability to fight infections. _Hormonal contraceptives_ are birth control methods that contain hormones, like progestin, to prevent pregnancy. The study will explore how these hormones might change the body's natural defenses and how these changes vary with different types of contraceptives. Women participating must not have HIV, be willing to use specific contraceptives (like a shot, implant, or IUD), and follow some rules like avoiding certain activities before visits.

• Study lasts up to 4 months with multiple visits.
• No vaginal intercourse or products 1 day before visits.
• Must agree to use certain hormone-based birth controls.