PIP: Despite skepticism on the part of the health care delivery system, increasing numbers of women and couples are relying on natural family planning methods to avoid or achieve pregnancy. Most clients require 2-4 cycles to become familiar with the delineation of the fertile phase. Both the ovulation and the sympto-thermal methods are considered to have a method effectiveness of at least 98%. Teaching-related unplanned pregnancies fall below 5%. Use of the Billings ovulation method requires the couple to abstain from intercourse from the beginning of mucus until the 4th day after peak. The sympto-thermal method is preferred by those desiring a multiple-index approach. 75-80% of users of this method can detect cervical softening and dilatation, and 50% are aware of the change of position of the cervix. Knowledge of mucus buildup patterns can be expecially important for adolescents, lactating women, and premenopausal women in helping them to determine whether cycles are ovulatory. Instruction in interpretation of the mucus cycle is further advised in cases of infertility. Unwillingness of the partners to practice it constitutes the only contraindication to natural family planning. However, couples are advised to wait for the postovulatory infertile phase of the cycle to have intercourse in cases where prgnancy would pose a serious threat to the life of the mother or fetus. Although some groups recommend the use of a barrier method rather than abstinence during fertile periods, this practice makes mucus recognition more difficult and impedes confidence in the method. Attainment of couple autonomy in natural family planning involves 2 phases: 1) correct recognition of the signs of fertility and 2) comfort with periodic asbsinence. Successful autonomy is reflected in the high continuation rates found in programs that offer adequate counseling support.