Birth control is an umbrella term for several techniques and methods used to prevent fertilization or to interrupt pregnancy at various stages. Birth control techniques and methods include contraception (the prevention of fertilization), contragestion (the prevention of the implantation of the blastocyst) and abortion (the removal or expulsion of a fetus or embryo from the uterus). Contraception includes barrier methods, such as condoms or diaphragm, hormonal contraception, also known as oral contraception, and injectable contraceptives. Contragestives, also known as post-coital birth control, include intrauterine devices and what is known as the morning after pill.