Fertility Awareness-Based Methods: Another Option for Family Planning

Stephen R. Pallone, MD; George R. Bergus, MD


J Am Board Fam Med. 2009;22(2):147-157. 

In This Article

Benefits and Harms

The lack of medical side effects and the low cost of FABMs are implicit benefits, but the social effects deserve some examination. Modern NFP methods are associated with a lower incidence of induced abortion.[43,45] They are also associated with a US divorce rate lower than that among the general US population.[43] One nonrandomized survey found the ever-divorced rate among NFP users was 2 in 1000 if they had never used other forms of contraception. Four percent of those who had used non-NFP types of contraception previously had been divorced.[43] In the same year, 10.8% of the general population identified themselves as presently divorced, with a divorce rate of 4.1 in 1000 per year.[52,53] Catholics who do not use NFP have divorce rates similar to those of the general population, suggesting that religion alone does not account for this difference.[43] The difference may be attributable to the methods or to selection bias, although neither has been clearly established. These effects have not been studied in FABMs.

Proponents of modern NFP often endorse improved communication, sexual interactions, deeper intimacy and respect for partners, and other aspects of psychosocial-spiritual well-being with NFP use. Evidence is insufficient to evaluate this claim, which is based on a single nonrandomized survey of NFP users.[43] Subsequent confirmation studies examining well-being have methodological flaws, such as incomplete reporting of data and mismatched comparison groups, making it difficult to assess the validity of these statements on a population level.[54,55] Most couples continuing to use NFP have mixed feelings about the methods, but responses are primarily positive.[56] These effect have not been studied in FABMs.

Another concern voiced about FABMs is the potential for decreased frequency of intercourse. Studies have found that coital frequency varies greatly by country, ranging from 2.6 to 8.9 acts per month; the worldwide average is approximately 5.5 acts per month among all couples. FABM users have an average monthly coital frequency of 5.1 acts per month.[57] Standard Days Method (SDM) and TwoDays Method (TDM) users average 5.5 and 5.6 acts per month, respectively.[58] The timing of intercourse does shift with the use of FABMs, becoming more frequent during identified nonfertile days. There is a small trend of increased frequency of intercourse as the users become more comfortable with their chosen method.[58] Although perceived lack of spontaneity of intercourse is raised as a concern related to FABM use, this aspect of FABMs has not been adequately studied.


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