Different contraceptives work in various ways to prevent pregnancy:
Barrier methods physically block sperm from reaching the egg. Hormonal methods prevent ovulation, thicken cervical mucus to block sperm, or thin the lining of the uterus to prevent implantation. IUDs can release hormones or create an environment in the uterus that is hostile to sperm and eggs. Sterilization involves surgical procedures that permanently prevent the release of eggs or sperm. Natural methods rely on identifying fertile days and avoiding intercourse during those times. Emergency contraception prevents or delays ovulation or prevents fertilization and implantation.
