A Little History
Before the 20th century a woman’s fertility and menstrual cycle was widely misunderstood in both medicine and popular culture. Many scientific discoveries over the last 150 years have led to our current understanding of the meaning of a woman’s monthly patterns of fertility. I’m going to summarize some of them here as context for
- In 1855, W. Tyler Smith observed that cervical fluid offers a medium well-suited for the passage of sperm and in 1868, J. Marim Sims described cervical fluid as having the consistency of a white of an egg.
- The first observations that the resting (basal) body temperature has a biphasic pattern (low temperatures followed by high temperatures) during the menstrual cycle were made by Squire in 1868 and Mary Putnam Jacobi in 1876. Neither, however, associated the thermal shift with ovulation.
- The finding that ovulation precedes menstruation by about 12-16 days and that this time is constant, was used by Kyusaku Ogino, in Japan and Hermann Knauss in Austria in the early 1930s.
- In 1962, Edward F. Keefe published observations of the physical changes of the cervix throughout the menstrual cycle.
The Development of Fertility Awareness Based Methods
- In the 1930‘s Ogino and Knaus, at the same time, but separately, used their finding that ovulation precedes menstruation by 12-16 days to develop the largely ineffective “calendar rhythm method” of birth control.
- In the 1950’s JGH Holt, a Dutch Gynecologist first presented the basal body temperature method to couples in an intelligible manner to regulate pregnancy.
- In 1968 John and Evelyn Billings in Australia developed a system, known as the “Billings” or “Ovulation” method to teach women how to observe and chart their cervical mucus signs to recognize their own fertility pattern.
- In 1981 the effectiveness of combining the indicators of fertility was increasingly recognized through prospective studies.
Studies on the Effectiveness of Fertility Awareness Method
Many researchers have studied the Fertility Awareness method with full scientific rigor. When women carefully use to the 5 Rules for Preventing Pregnancy, the results are clear:
- Perfect Use – 99.4% – 99.6% effective at preventing unintended pregnancy with use of doring-rotzer rule.
- Typical Use – 97.8% – 98.6% effective at preventing unintended pregnancy with use of the doring-rotzer rule.
These rates are comparable to many of the most trusted contraceptives for preventing pregnancy but do not share the same health risks and side effects of hormonal contraceptives and other widely used methods. (Important note: the Fertility Awareness Method alone does NOT protect the use from the spread of sexually-transmitted infections – barrier methods are essential to prevent STIs.)
One statistical report suggests that FAM has a lower effectiveness rate. The data in question comes from a periodic survey conducted in the U.S. that asks women who became pregnant unexpectedly in the past year to report which method of contraceptive they were using at the time of conception. The author of this study has admitted that this statistic does not take into consideration the wide variety of Fertility Awareness Based Methods or the way that they learned use of the method. Therefore this widely cited statistic is misleading and offers misinformation to both physicians and the wider population.
Want to dig deeper? References:
- Frank-Hermann P, Heil J, Gnoth C et al. The Effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple’s sexual behavior during the fertile time: a prospective longitudinal study.
- Frank-Hermann P, Freundl G, Gnoth C et al. Natural family planning with and without barrier method use in the fertile phase: efficacy in relation to sexual behavior: a German prospective long-term study.
- Manhart M, Duane M, Lind A et al. Fertility awareness-based methods of family planning: A review of effectiveness for avoiding pregnancy using SORT.
- www.fertilityfriend.com A brief history of fertility charting.
- Pyper C, Knight J. Fertility Awareness Methods of Family Planning for Achieving or Avoiding Pregnancy.