One of the biggest reservations people face when deciding to use fertility awareness as a method of birth control is effectiveness. Thanks to the misinformation around fertility awareness and the rhythm method (more commonly called cycle tracking or period tracking in recent times) many women are sceptical that fertility awareness can provide effective birth control.
In order to assess the effectiveness of birth control, scientists use two categories, the “perfect use” category and the “typical use” category. Perfect use means that the method is used perfectly each time. Perfect use effectiveness rates are calculated in clinical trials. While it is possible for any birth control to be used perfectly each time, it is unlikely to occur in everyday life. Typical use rates are calculated by surveying large population groups in different demographics to get a more accurate representation of the accuracy of birth control in everyday life. Typical use allows for human error and is more reflective of true effectiveness.
All contraception types that rely on the use of the person have a higher failure rate. This is because there is greater room for human error like forgetting or taking risks. This includes methods like the pill, all barrier methods including condoms and FAM methods. In contrast, an option like an implant or IUD can not be tampered with so failure rates are very low.
The effectiveness of FAM methods depends on the type of FAM method used. Most FAM methods range in effectiveness from 77%-98% effective. Rhythm methods which are sometimes confused with FAM methods are about 70% effective and only work for women with regular cycles some of the time. Symptothermal FAM methods are the most reliable. The best estimate of the effectiveness of FAM is based on a study conducted in Germany on over 900 women over a period of 13 menstrual cycles. The study concluded with a perfect use rate of 99.6% with abstinence being observed in the fertile window and 99.4% with a barrier method being used in the fertile window (1). The study design involved a qualified fertility awareness instructor to ensure accurate results and was conducted using the Sensiplan method. There are currently no studies assessing the typical use of sympto-thermal methods so typical use is calculated based on clinical trials and is estimated to be about 98.4%.
There is definitely a need for more research into the effectiveness of sympto-thermal methods. With the rise in the popularity of cycle tracking and fertility awareness, I am confident that more research will follow. In the meantime, fertility awareness offers an effective form of birth control without side effects and also has the added benefit of improving body literacy and being used as a tool to assess hormone health and overall health.
Below I have added some graphics of the most popular hormonal and non-hormonal birth control options the effectiveness based on typical use and perfect use. As always the birth control choices of any person are highly individual. FAM is a wonderful birth control option that can be used by the majority of women, however different life circumstances might make FAM unsuitable for many women.
Please note** most research on the effectiveness of FAM has been conducted under the guidance of a qualified instructor. While FAM can easily be self-taught, there is no quality data on the effectiveness of FAM without the guidance of an instructor. If you wish to work with me to learn the FAM method please contact me or book an appointment.
(1) Frank-Herrmann, P., Heil, J., Gnoth, C., Toledo, E., Baur, S., Pyper, C., Jenetzky, E., Strowitzki, T., & Freundl, G. (2007). The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behaviour during the fertile time: a prospective longitudinal study. Human reproduction (Oxford, England), 22(5), 1310–1319. https://doi.org/10.1093/humrep/dem003