U.S. National Library of Medicine

1. Natural Family Planning Methods

   A class of natural contraceptive methods in which SEXUAL ABSTINENCE is practiced a few days before and after the estimated day of ovulation, during the fertile phase. Methods for determining the fertile period or OVULATION DETECTION are based on various physiological indicators, such as circulating hormones, changes in cervical mucus (CERVIX MUCUS), and the basal body temperature.