Recommendations for Contraceptive Use
		Natural Family Planning

Recommendations	Rationale
a) NFP Effectiveness Estimates of NFP effectiveness vary widely.	a) NFP effectiveness depends upon several factors, including: the indicator(s) used, the validity of the rules used, the type and quality of teaching, the ability of the woman to observe and interpret her fertility signs, the ability of the couple to abstain from vaginal intercourse when indicated by the rules, and individual characteristics of the couple, such as the age of the woman and her past history of pelvic infection or other determinants of lowered fertility.
b) Calendar-based methods Estimates from clearly reported trials which state the rule used range from 5% to 14%. A recent re-analysis of calendar method clinical studies found a typical failure rate estimate of about 20%.	b) It is difficult to estimate the effectiveness of the calendar method because very few well-designed studies have been conducted. Many of the estimates are based upon surveys and do not report the requisite information required to calculate effectiveness rates. It is difficult to compare studies on the calendar method because many reports do not state what rule was used to identify the fertile time or if couples understood the basis for the method. Dicker D, Wachsman Y, Feldberg D. The vaginal contraceptive diaphragm and the condom: a reevaluation and comparison of two barrier methods with the rhythm method. Contraception 1989; 40(4):497-504. Laing J. Periodic abstinence in the Philippines: new findings from a national survey. Studies in Family Planning 1987;18(1):32-41.
c) Single indicator methods (basal body temperature (BBT), cervical mucus or ovulation methods) Estimates range from 3% with perfect use to about 20% with typical use.	c) The probability of accidental pregnancy when using single indicator methods is highest when couples do not abstain during the fertile period. For users of the cervical mucus or ovulation methods, having intercourse during periods of stress on the woman also increases the risk of pregnancy by affecting the quality of mucus. Stress, illness, travel or interrupted sleep can disrupt a woman's typical biphasic pattern, thereby making it difficult to identify the fertile period for that cycle using the BBT method. World Health Organization. A prospective multicentre trial of the ovulation method of natural family planning II. The effectiveness phase. Fertility and Sterility 1981; 35(5):591-8. Trussell J, Grummer-Strawn L. Contraceptive failure of the ovulation method of periodic abstinence. Family Planning Perspectives 1990;22:65-75. Hatcher RA, Trussell J, Stewart F, Stewart GK, Kowal D, Guest F, et al. Fertility Awareness. In: Contraceptive Technology. New York: Irvington Publishers, 1994:327-40.
d) Two or more indicator methods (symptothermal methods) Estimates range from about 2% with perfect use to about 15% to 20% with typical use.	d) The use of two or more indicators can be somewhat more effective than the use of a single indicator. Hatcher RA, Trussell J, Stewart F, Stewart GK, Kowal D, Guest F, et al. Fertility Awareness. In: Contraceptive Technology. New York: Irvington Publishers, 1994:327-40. Frank-Herrmann P, Freundl G, Baur S, Bremme M, Doring G, Godehardt E, et al. Effectiveness and acceptability of the symptothermal method of natural family planning in Germany. American Journal of Obstetrics and Gynecology 1991;165:2052-4.

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