Plan B and other medical regimens are available for emergency contraception. They provide a large dose of progestins to suppress ovulation. This is NOT the same as RU486, the abortion pill which causes abortion. Instead it is a contraceptive that prevents pregnancy in the first place. It is only for use in emergencies when it is feared that there was a failure of your chosen method of birth control (ex: the condom broke). It is available over the counter and without a prescription for women above the age of 18.