Fertility awareness is a type of natural family planning based on a woman's physical signs of ovulation, such as changes in cervical mucus consistency and basal (resting) body temperature. Keeping track of these symptoms may be helpful if a couple is trying to become pregnant or trying to avoid pregnancy.

• If a woman is trying to become pregnant, having sex during the 5 days before she ovulates and the day she ovulates increases her chances of success.
• If a woman is trying to avoid pregnancy, avoiding sex until several days after she has ovulated helps prevent pregnancy (the human egg is typically fertile for only 12 to 24 hours after ovulation).

Because intercourse before ovulation can lead to pregnancy, and ovulation does not always occur at the same time every month, fertility awareness is not the most reliable method of avoiding pregnancy.