Fertility awareness

It is not known exactly when it was first discovered that women have predictable periods of fertility and infertility. It is already clearly stated in the Talmud tractate Niddah, that a woman only becomes pregnant in specific periods in the month, which seemingly refers to ovulation. St. Augustine wrote about periodic abstinence to avoid pregnancy in the year 388 (the Manichaeans attempted to use this method to remain childfree, and Augustine condemned their use of periodic abstinence).[8] One book states that periodic abstinence was recommended "by a few secular thinkers since the mid-nineteenth century,"[9] but the dominant force in the twentieth century popularization of fertility awareness-based methods was the Roman Catholic Church.

In 1905 Theodoor Hendrik van de Velde, a Dutch gynecologist showed that women only ovulate once per menstrual cycle.[10] In the 1920s, Kyusaku Ogino, a Japanese gynecologist, and Hermann Knaus, from Austria, independently discovered that ovulation occurs about fourteen days before the next menstrual period.[11] Ogino used his discovery to develop a formula for use in aiding infertile women to time intercourse to achieve pregnancy. In 1930, John Smulders, a Roman Catholic physician from the Netherlands, used this discovery to create a method for avoiding pregnancy. Smulders published his work with the Dutch Roman Catholic medical association, and this was the first formalized system for periodic abstinence: the rhythm method.[11]

In the 1930s, Reverend Wilhelm Hillebrand, a Catholic priest in Germany, developed a system for avoiding pregnancy based on basal body temperature.[12] This temperature method was found to be more effective at helping women avoid pregnancy than were calendar-based methods. Over the next few decades, both systems became widely used among Catholic women. Two speeches delivered by Pope Pius XII in 1951 gave the highest form of recognition to the Catholic Church's approval—for couples who needed to avoid pregnancy—of these systems.[9][13] In the early 1950s, John Billings discovered the relationship between cervical mucus and fertility while working for the Melbourne Catholic Family Welfare Bureau. Billings and several other physicians, including his wife, Dr. Evelyn Billings, studied this sign for a number of years, and by the late 1960s had performed clinical trials and begun to set up teaching centers around the world.[14]

While Dr. Billings initially taught both the temperature and mucus signs, they encountered problems in teaching the temperature sign to largely illiterate populations in developing countries. In the 1970s they modified the method to rely on only mucus.[12] The international organization founded by Dr. Billings is now known as the World Organization Ovulation Method Billings (WOOMB).

The first organization to teach a symptothermal method was founded in 1971. John and Sheila Kippley, lay Catholics, joined with Dr. Konald Prem in teaching an observational method that relied on all three signs: temperature, mucus, and cervical position. Their organization is now called Couple to Couple League International.[12] The next decade saw the founding of other now-large Catholic organizations, Family of the Americas (1977), teaching the Billings method,[15] and the Pope Paul VI Institute (1985), teaching a new mucus-only system called the Creighton Model.[16]

Up until the 1980s, information about fertility awareness was only available from Catholic sources.[17] The first secular teaching organization was the Fertility Awareness Center in New York, founded in 1981.[18] Toni Weschler started teaching in 1982 and published the bestselling book Taking Charge of Your Fertility in 1995.[19] Justisse was founded in 1987 in Edmonton, Canada.[20] These secular organizations all teach symptothermal methods. Although the Catholic organizations are significantly larger than the secular fertility awareness movement, independent secular teachers have become increasingly common since the 1990s.

Development of fertility awareness methods is ongoing. In the late 1990s, the Institute for Reproductive Health at Georgetown University introduced two new methods.[21][22] The Two-Day Method, a mucus-only system, and CycleBeads and iCycleBeads (the digital version), based on the Standard Days Method, are designed to be both effective and simple to teach, learn, and use. In 2019, Urrutia et al. released a study as well as interactive graph over-viewing all studied fertility awareness based methods.[3] Femtech companies such as Dot[23] and Natural Cycles have also produced new studies and apps to help women avoid pregnancy. Natural Cycles is the first app of its kind to receive FDA approval.[24]

This usually refers to a temperature reading collected when a person first wakes up in the morning (or after their longest sleep period of the day). The true BBT can only be obtained by continuous temperature monitoring through internally worn temperature sensors. In women, ovulation will trigger a rise in BBT between 0.2º and 0.5 °C. (0.5 and 1.°F) that lasts approximately until the next menstruation. This temperature shift may be used to determine the onset of post-ovulatory infertility. (See ref. 30)

The appearance of cervical mucus and vulvar sensation are generally described together as two ways of observing the same sign. Cervical mucus is produced by the cervix, which connects the uterus to the vaginal canal. Fertile cervical mucus promotes sperm life by decreasing the acidity of the vagina, and also it helps guide sperm through the cervix and into the uterus. The production of fertile cervical mucus is caused by estrogen, the same hormone that prepares a woman's body for ovulation. By observing her cervical mucus and paying attention to the sensation as it passes the vulva, a woman can detect when her body is gearing up for ovulation, and also when ovulation has passed. When ovulation occurs, estrogen production drops slightly and progesterone starts to rise. The rise in progesterone causes a distinct change in the quantity and quality of mucus observed at the vulva.[25]

The cervix changes position in response to the same hormones that cause cervical mucus to be produced and to dry up. When a woman is in an infertile phase of her cycle, the cervix will be low in the vaginal canal; it will feel firm to the touch (like the tip of a person's nose); and the os—the opening in the cervix—will be relatively small, or "closed". As a woman becomes more fertile, the cervix will rise higher in the vaginal canal, it will become softer to the touch (more like a person's lips), and the os will become more open. After ovulation has occurred, the cervix will revert to its infertile position.

• There are no drug-related side effects to FA.[37]
• FA can be free or have a very low up-front cost. Users may employ a coach, use computer software, or buy a chart, calendar, or basal thermometer. The direct costs are low when compared to other methods.
• FA can be used with barrier contraception so that intercourse may continue through the fertile period. Unlike barrier use without FA, practicing FA can allow couples to use barrier contraception only when necessary.
• FA can be used to immediately switch from pregnancy avoidance to pregnancy planning if the couple decides it is time to plan for conception.

• Use of a barrier or other backup method is required on fertile days; otherwise the couple must abstain. To reduce pregnancy risk to below 1% per year, there are an average of 13 days where abstinence or backup must be used during each cycle.[38] For women with very irregular cycles—such as those common during breastfeeding, perimenopause, or with hormonal diseases such as PCOS—abstinence or the use of barriers may be required for months at a time.
• Typical use effectiveness is lower than most other methods.[39]
• Fertility awareness does not protect against sexually transmitted disease.[40]

The effectiveness of fertility awareness, as of most forms of contraception, can be assessed two ways. Perfect use or method effectiveness rates only include people who follow all observational rules, correctly identify the fertile phase, and refrain from unprotected intercourse on days identified as fertile. Actual use or typical use effectiveness rates include all women relying on fertility awareness to avoid pregnancy, including those who fail to meet the "perfect use" criteria. Rates are generally presented for the first year of use.[41] Most commonly, the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables.[42]

The failure rate of fertility awareness varies widely depending on the system used to identify fertile days, the instructional method, and the population being studied. Some studies have found actual failure rates of 25% per year or higher.[43][44][45] At least one study has found a failure rate of less than 1% per year with continuous intensive coaching and monthly review,[46] and several studies have found actual failure rates of 2%–3% per year.[38][47][48][49]

When used correctly and consistently (i.e., with perfect use) with ongoing coaching, under study conditions some studies have found some forms of FA to be 99% effective.[46][50][51][52]

From Contraceptive Technology:[53]

• Post-ovulation methods (i.e., abstaining from intercourse from menstruation until after ovulation) have a method failure rate of 1% per year.
• The symptothermal method has a method failure rate of 2% per year.
• Cervical mucus–only methods have a method failure rate of 3% per year.
• Calendar rhythm has a method failure rate of 9% per year.
• The Standard Days Method has a method failure rate of 5% per year.

Several factors account for typical-use effectiveness being lower than perfect-use effectiveness:

• conscious user non-compliance with instructions (having unprotected intercourse on a day identified as fertile)
• mistakes on the part of those providing instructions on how to use the method (instructor providing incorrect or incomplete information on the rule system)
• mistakes on the part of the user (misunderstanding of rules, mistakes in charting)

The most common reason for the lower actual effectiveness is not mistakes on the part of instructors or users, but conscious user non-compliance[38][52]—that is, the couple knowing that the woman is likely to be fertile at the time but engaging in sexual intercourse nonetheless. This is similar to failures of barrier methods, which are primarily caused by non-use of the method.

A 2015 review found insufficient evidence to draw any conclusions about the effect of timing intercourse on the rate of live births or pregnancies, compared to regular intercourse.[54]

A study by Barrett and Marshall has shown that random acts of intercourse achieve a 24% pregnancy rate per cycle. That study also found that timed intercourse based on information from a BBT-only method of FA increased pregnancy rates to 31%–68%.

Studies of cervical-mucus methods of fertility awareness have found pregnancy rates of 67–81% in the first cycle if intercourse occurred on the Peak Day of the mucus sign.[55][56]

Because of high rates of very early miscarriage (25% of pregnancies are lost within the first six weeks since the woman's last menstrual period, or LMP), the methods used to detect pregnancy may lead to bias in conception rates. Less-sensitive methods will detect lower conception rates, because they miss the conceptions that resulted in early pregnancy loss. A Chinese study of couples practicing random intercourse to achieve pregnancy used very sensitive pregnancy tests to detect pregnancy. It found a 40% conception rate per cycle over the 12-month study period.[57]

Pregnancy rates for sexual intercourse are also affected by several other factors. Regarding frequency, there are recommendations of sexual intercourse every 1 or 2 days,[58] or every 2 or 3 days.[59] Studies have shown no significant difference between different sex positions and pregnancy rate, as long as it results in ejaculation into the vagina.[60]

Social science research has found that timing intercourse can become a gendered 'chore' in heterosexual married couples trying to conceive, with women tracking their ovulation cycles and dictating to their husbands when they should have sexual intercourse.[61]

Regular menstrual cycles are sometimes taken as evidence that a woman is ovulating normally, and irregular cycles as evidence she is not.[62] However, many women with irregular cycles do ovulate normally, and some with regular cycles are actually anovulatory or have a luteal phase defect. Records of basal body temperatures, especially, but also of cervical mucus and position, can be used to accurately determine if a woman is ovulating, and if the length of the post-ovulatory (luteal) phase of her menstrual cycle is sufficient to sustain a pregnancy.

Fertile cervical mucus is important in creating an environment that allows sperm to pass through the cervix and into the fallopian tubes where they wait for ovulation. Fertility charts can help diagnose hostile cervical mucus, a common cause of infertility. If this condition is diagnosed, some sources suggest taking guaifenesin in the few days before ovulation to thin out the mucus.[63]

Pregnancy tests are not accurate until 1–2 weeks after ovulation. Knowing an estimated date of ovulation can prevent a woman from getting false negative results due to testing too early. Also, 18 consecutive days of elevated temperatures means a woman is almost certainly pregnant.[64]

Estimated ovulation dates from fertility charts are a more accurate method of estimating gestational age than the traditional pregnancy wheel or last menstrual period (LMP) method of tracking menstrual periods.[65]