Abstract: "Natural" methods of contraception are preferred by some halachic authorities for couples with less compelling reasons to delay pregnancy. Thus, couples may wish to use the Fertility Awareness Method. Because observant couples already abstain for a minimum of 12 days per cycle due to the rules of niddah, adjustments may have to be made in the use of this method.
FAM may be halachically recommended even when the couple is permitted to use other methods, such as spermicide or a diaphragm, in order to limit the use of these contraceptives to the times of actual fertility or together with these methods to increase the efficacy of spermicides alone.
Discussion: The fertility awareness methods (FAM) are a natural form of contraception based on recognizing bodily changes caused by the fluctuation of estrogen and progesterone during the menstrual cycle. When used correctly and consistently, these methods enable women to identify the time surrounding ovulation when intercourse is likely to lead to conception. When trying to avoid pregnancy, the couple can either avoid relations during the fertile period or use a barrier-based method such as spermicide with or without a diaphragm (the latter being more effective). FAM techniques can also be used for the opposite purpose, to optimize chances of conception when a couple is trying to achieve pregnancy.
There are a number of forms of FAM. Older forms based on the calendar alone are not very effective. However, modern methods are based on the following scientific principles:
- Hormonal fluctuation causes recognizable changes in basal body temperature, consistency of cervical fluid and the position of the cervix.
- The ovum lives only 12-24 hours,
- Sperm can live for about 5 days in fertile-quality secretions and
- The corpus luteum inhibits further ovulation from about 24 hours after ovulation for about two weeks.
The various forms of FAM differ as to which of the following are measured:
Basal Body Temperature (BBT) - Oral temperature is taken each morning after a night's rest of at least 3 hours and charted. A consistent rise means that ovulation has taken place. Once this rise is verified, and three days have passed, a woman is no longer fertile for the rest of the cycle.
Cervical Secretions are checked prior to urination throughout the day. This is generally done at the vaginal opening. Cervical secretions change throughout the cycle in response to the hormonal changes of the cycle. The cervical mucus differs slightly between the follicular and luteal phases. During the follicular phase it tends to be clear, thin, and watery and typically not very noticeable to the woman. At ovulation the secretions become milkier, wetter, and thinner, and resemble egg-white. The progesteronal effect on cervical mucus during the luteal phase makes it thick, yellow, creamy, or even crusty or green.
Changes in Cervical Position occur only at the time of ovulation. By inserting a finger deep in the vagina, a woman can recognize the changes before, during, and after ovulation. On infertile days, the cervix is lower, closed, and hard. At ovulation it moves upwards towards the uterus, opens, and softens.
The more signs a woman checks, the more reliable the method. In order to be effective, FAM should be learned with a qualified teacher. A number of medical apps have been devised that claim to be a form of FAM. However, most have been found to be inaccurate. 
Avoiding relations during the fertile period (which, for the observant couple, means only the post ovulatory phase) can shorten the time available to the couple for marital relations (depending on the woman's cycle length). In particular, mikveh night, when it is considered a mitzvah to have relations, often falls during the fertile period. Some rabbinic authorities allow the woman to immerse for the purpose of physical contact and closeness without intercourse. Others recommend that the couple delay mikveh immersion.
Although FAM is a 'natural' method and involves no external intervention, it is still a form of birth control. FAM may be used for contraception only where the couple is halachically permitted to delay pregnancy.
FAM may be halachically recommended even when the couple is permitted to use other methods, such as spermicide or a diaphragm, in order to limit the use of these contraceptives to the times of actual fertility.
Implications for Patient Care: Some couples may wish to use the Fertility Awareness Method, either fully or partially. Therefore, practitioners should be aware of this method in order to best advise their patients as to how it works and whether it is sufficient for their contraceptive needs, and to refer them to appropriate educators. The days available for intercourse will be fewer than in the general population due to the limitations of the laws of niddah.
 Pallone SR, Bergus GR. Fertility awareness-based methods: another option for family planning. J Am Board Fam Med. 2009;22:147-57
 Weschler T. Taking Charge of Your Fertility, 20th Anniversary Edition: The Definitive Guide to Natural Birth Control, Pregnancy Achievement, and Reproductive Health. HarperCollins, 2017.
 Duane M, Contreras A, Jensen ET, White A. The Performance of Fertility Awareness-based Method Apps Marketed to Avoid Pregnancy. J Am Board Fam Med. 2016 Jul-Aug;29(4):508-11.
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