Birth control, also known as contraception, is the use of medicines, devices, or surgery to prevent pregnancy. There are many different types of birth control methods available, including barrier methods, hormonal methods, and natural rhythm methods. Barrier methods, such as condoms and diaphragms, prevent sperm from reaching the egg, while hormonal methods, such as the birth control pill, prevent ovulation or thicken cervical mucus to block sperm. Natural rhythm methods involve avoiding sex or using other forms of birth control on the days when a person is most fertile. Emergency contraception is also available to prevent pregnancy after unprotected intercourse or if a condom breaks. Birth control methods can be reversible or permanent, and some types can also help prevent sexually transmitted diseases (STDs) . It is important to choose a birth control method that works best for an individuals needs and lifestyle, and to use it correctly and consistently to prevent unintended pregnancy.