Context: Fertility awareness-based (FAB) methods of family planning estimate the fertile days of the menstrual cycle whether by observing fertility signs such as cervical secretions and basal body temperature or by monitoring cycle days. The efficacy and acceptability of these methods are unclear.
Methods: We retrieved and analyzed all randomized controlled trials that examined any FAB method used for contraception.
Results: Because of poor methods and reporting, pregnancy rates could not be determined. A trial in Colombia found similar numbers of pregnancies among women randomized to the ovulation and symptothermal methods, but a trial in Los Angeles observed more pregnancies in the group assigned to the ovulation method. In the two American trials, recruitment of participants was unexpectedly difficult. Continuation rates were poor.
Conclusion: Despite intensive training and ongoing support, most participants in these trials discontinued prematurely. The comparative efficacy of these methods remains unknown. However, with the ovulation and symptothermal methods, pregnancies appear to be common; method continuation rates are low.