Periodic abstinence: Also known as fertility awareness, natural family planning, and the rhythm method, this approach entails not having sexual intercourse on the days of a woman's menstrual cycle when she could become pregnant or using a barrier method (such as a condom, the diaphragm or a cervical cap) for birth control on those days.
Because a sperm may live in the female's reproductive tract for up to 7 days and the egg remains fertile for about 24 hours, a woman can get pregnant within a substantial window of time -- from 7 days before ovulation to 3 days after. Methods to approximate when a woman is fertile are usually based on the menstrual cycle, changes in cervical mucus, or changes in body temperature. This approach to birth control will likely fail and the woman to become pregnant.
