Fertility awareness-based methods for contraception

Abstract

Background: 'Fertility awareness-based methods' of family planning "involve identification of 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. Fertility awareness-based methods can be used in combination with abstinence or barrier methods during the fertile time" (WHO 2000). Several names have been used to describe this approach to contraception, including 'rhythm,' 'natural family planning' and 'periodic abstinence.' Fertility awareness-based methods can be used with abstinence from sexual intercourse. Alternatively, they can be used with barrier contraceptives or withdrawal during presumed fertile times. Objectives: We retrieved and analyzed all randomized controlled trials (RCTs) that examined any fertility awareness-based methods used for contraception. Search methods: In February 2012, we searched the computerized databases CENTRAL, MEDLINE, POPLINE, and LILACS for randomized controlled trials of fertility awareness-based methods. We also searched for trials in ClinicalTrials.gov and ICTRP. Previous searches also included EMBASE. For the initial review, we examined the reference lists of trial reports as well as that of review articles. Selection criteria: We included all RCTs in any language that compared any fertility awareness-based methods for contraception with a placebo; another method, including an alternative fertility awareness-based method; or fertility awareness-based methods used in conjunction with another contraceptive. Data collection and analysis: We assessed all titles and abstracts found for inclusion. We evaluated the methodological quality of the trials for potential biases by qualitatively assessing the study design, randomization method, allocation concealment, blinding, premature discontinuation rates, and loss to follow-up rates. Because of methodological weaknesses, we could not enter the trial results in RevMan, calculate measures of association, or aggregate data. Main 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. In contrast, a companion trial in Los Angeles observed more pregnancies in the group assigned to the ovulation method. In the two USA trials, recruitment of participants was unexpectedly difficult; this aspect was not mentioned in the report from Colombia. Continuation rates were poor. In the two larger trials, most participants discontinued their assigned method before entering the observation phase of the trial. Authors' conclusions: The comparative efficacy of fertility awareness-based methods of contraception remains unknown. Despite intensive training and ongoing support, most participants in these trials discontinued prematurely. Contraceptive methods should be properly evaluated, preferably in randomized controlled trials, before adoption and dissemination.