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

Abstract and Introduction


Modern fertility awareness-based methods (FABMs) of family planning have been offered as alternative methods of family planning. Billings Ovulation Method, the Creighton Model, and the Symptothermal Method are the more widely used FABMs and can be more narrowly defined as natural family planning. The first 2 methods are based on the examination of cervical secretions to assess fertility. The Symptothermal Method combines characteristics of cervical secretions, basal body temperature, and historical cycle data to determine fertility. FABMs also include the more recently developed Standard Days Method and TwoDays Method. All are distinct from the more traditional rhythm and basal body temperature methods alone. Although these older methods are not highly effective, modern FABMs have typical-use unintended pregnancy rates of 1% to 3% in both industrialized and nonindustrialized nations. Studies suggest that in the United States physician knowledge of FABMs is frequently incomplete. We review the available evidence about the effectiveness for preventing unintended pregnancy, prognostic social demographics of users of the methods, and social outcomes related to FABMs, all of which suggest that family physicians can offer modern FABMs as effective means of family planning. We also provide suggestions about useful educational and instructional resources for family physicians and their patients.


Fertility awareness-based methods (FABMs) of family planning are methods that use physical signs and symptoms that change with hormone fluctuations throughout a woman's menstrual cycle to predict a woman's fertility. The unifying theme of FABMs is that a woman can reduce her chance of pregnancy by abstaining from coitus or using barrier methods during times of fertility. Natural family planning (NFP) is a subset of FABMs that specifically excludes concurrent use of all other forms of contraception, including barriers, as a supplement to the observation for fertile signs; pregnancy is avoided through abstinence alone.[1]

Several factors contribute to a woman's fertility. An ovum survives up to 24 hours after ovulation unless it is fertilized, leaving a finite time for sperm to reach the egg. Sperm have short life spans after ejaculation without hospitable cervical mucous, which is present only in the periovulatory period. In optimum conditions, the typical maximum life span of sperm is 5 days, leaving a fertile window of approximately 6 days.[2,3] Although FABMs may be used to achieve pregnancy, that discussion is beyond the scope of this review.

FABMs are diverse. They include the older calendar ("rhythm")- and basal body temperature-based methods and the newer methods that assess cervical mucous or a combination of signs and symptoms (which include the older methods). The former are generally not considered to be highly effective.[4] The newer methods compare favorably with conventional contraceptives (Table 1 and Table 2). It is not certain where providers and patients obtain their information about FABMs. Anecdotal evidence suggests that in the United States instruction is not often available through physician providers, occasionally through hospital programs, and more often available from faith-based groups.

When provided with positive information about FABMs more than 1 in 5 women in the United States expressed interest in using one of these methods to avoid pregnancy.[36,37] However, only 1% to 3% percent of US women are currently using an FABM for this purpose.[36,38] Despite an improved understanding of the science underlying FABMs, rates of use have declined to 11% from 22% of married couples in 1955.[37,39] This decline is multifactorial. Clinicians and patients frequently perceive a difficulty in learning the methods.[36,40,41] Many women also believe FABM are not efficacious.[36,40,41] Many physicians do not have the knowledge to teach their patients about these methods. One geographically limited study found that physicians have significant knowledge deficits about FABMs[41] and that they generally know less about these methods than do nurse midwives.[42] Another survey of NFP users showed that only 1% of them came to use those methods because of the advice of medical practitioners.[43]


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