June 26, 2018
By Marguerite R. Duane, MD and Erin Adams, MD

Editor’s Note: Last week, Drs. Marguerite Duane and Erin Adams provided a brief summary of how the various fertility awareness based methods (FABMs) evolved over the last century. They reviewed the groundbreaking work of scientists from various parts of the world, each of whom was instrumental in the evolution of these methods from the laboratory to practical applications for women and couples.

Woman charting with FABMs


Beyond the ovulation and sympto-thermal methods discussed last week, the authors now discuss the sympto-hormonal and simplified methods of family planning as well as significant scientific developments in natural family planning since the rhythm method was first described nearly a century ago.

Sympto-Hormonal Methods
In the 1990s, Dr. Richard Fehring developed the Marquette Model at Marquette University. This Sympto-Hormonal Method uses cervical mucus observations together with hormone readings from the ClearBlueâ Easy Fertility Monitor to determine the probable time of ovulation.[i] This well-researched method has been shown to be effective in helping couples prevent pregnancy even during transitional times, such as the post-partum and peri-menopausal periods.[ii],[iii], [iv], [v]

In the most recent research involving the Marquette Model, the correct use unintended pregnancy rate was 1.6 per 100 women at both 12 and 24 months of use for all study participants.[vi] With typical use, after 12 months, the effectiveness rate for the electronic fertility monitor plus algorithm was 98% and for the monitor plus mucus observations, the method was 93% effective. In a study of breastfeeding women, there was no significant difference in effectiveness rates for women that used the electronic fertility monitor plus algorithm versus the monitor plus mucus observations. With correct use, the unintended pregnancy rate was 3 per 100 women years; with typical use, it was 14 per 100 women years.[vii]

In the last decade, we have seen the introduction of FEMM, the Fertility Education and Medical Management Model, which combines careful observations of cervical fluid with luteinizing hormone (LH) strip readings to track the phases of the female cycle.[viii] The primary focus of FEMM is to teach women to monitor their cycles so they may understand and manage their health more effectively. No studies have been conducted yet to evaluate the effectiveness of FEMM as a family planning method.

Simplified Methods
Over the last 20 years, researchers and clinicians at Georgetown University’s Institute for Reproductive Health (IRH) have developed simplified forms of both the cervical fluid and calendar based methods. One advantage of these simplified methods is that they are easy to teach and use. A criticism is that they are not flexible enough to follow the cycle-to-cycle variability that women experience.

The TwoDay Method is based on a woman’s observation of whether cervical secretions are present or absent to identify potential days of fertility. This method does not require interpretations of the quality of the secretions. With correct use, the TwoDay method is 96% effective and with typical use it is 86% effective.[ix]

The Standard Days Method (SDM), sometimes referred to as the CycleBeads method is a simplified calendar method that identifies a fixed fertile window. The SDM estimates the 6-day fertile phase of the menstrual cycle will fall within days 8-19 of the cycle, based on computer analysis of 7,500 menstrual cycles. An efficacy trial found that the SDM was more than 95% effective with correct use and more than 88% effective with typical use among women who reported regular recent cycles lasting 26–32 days.[x]

The Lactational Amenorrhea Method (LAM) may be used by women for the first six months after delivery, as long as the woman is exclusively breastfeeding her baby and does not have a return of her menses.[xi] Effectiveness rates for LAM are very high, greater than 98%, with both typical and correct use.[xii]


Significant Advances Since the Advent of the Rhythm Method

Over the past sixty years, significant advances have been made in the field of women’s reproductive health, especially as it pertains to tracking the signs of the female cycle that determine the periods of sterility and fertility. Based on these scientific advances, more effective forms of natural or fertility awareness based methods of family planning have been developed that allow women to identify their potential days of fertility in real time. Clearly, this is a major improvement over the Calendar-Rhythm method, which uses retrospective or historical data to predict future fertility.

Despite advances in the knowledge and application of FABMs for reproductive health and family planning, medical students and other health professional students receive little or no training in the effectiveness and practical applications of these methods. Regrettably, a majority of medical professionals still report they are most familiar with the antiquated Rhythm Method.

When the Rhythm Method was first introduced almost ninety years ago, it was a major scientific advance. Ironically, around the time the Rhythm Method was developed, the first antibiotic, penicillin, was discovered; a decade and a half later, penicillin was being mass-produced[xiii]. Since then, many different classes of antibiotics have been discovered and disseminated for use around the globe, which has revolutionized the way medical professionals treat infectious diseases. Yet, when it comes to the sciencific advances made over nine decades in understanding a woman’s cycle and the development of modern FABMs, most medical professionals still lack this knowledge.

In medicine, a field that prides itself in promoting the most current, evidence-based forms of care, this begs the question, why don’t medical professionals routinely learn about modern FABMs? This deficiency in medical education neglects the needs of these future medical professionals and the patients they will serve, who show increasing interest in these methods and may benefit from alternatives to artificial contraception.


Author Bios:

Marguerite R. Duane, MD is Executive Director and co-founder of FACTS. She travels and writes extensively to educate medical professionals about the effectiveness and benefits of FABMs. Dr. Duane teaches a 2-week online elective for medical students on the basics of FABMs through Georgetown University School of Medicine. Her recent interview on the Fertility Friday podcast provides an excellent overview and intriguing facts about fertility awareness (her interview begins 3 minutes and 30 seconds into the podcast).

Erin Adams, MD will soon begin her medical residency in Anesthesiology at Weill Cornell Medical College. She is a graduate of Georgetown University School of Medicine, where she completed a first year elective on FABMs with Dr. Duane and participated in a number of research projects. We are very grateful for her contributions to the mission of FACTS as a Student Ambassador.



Learn more about the Marquette Model.
For Spanish, click here.

Learn more about FEMM.
For Spanish, click here.

Learn more about the TwoDay Method.
For Spanish, click here. 

Learn more about the Standard Days Method.
For Spanish, click here.

Learn more about Lactational Amenorrhea Method.
For Spanish, click here.



At FACTS, our goal is to share the best evidence available with our healthcare colleagues and students so they can educate women and men about their fertility, empower them to make more informed choices about family planning, and enable women to collaborate with medical professionals to monitor and manage their reproductive health.

Join FACTS and enjoy these and other benefits of membership:
  • FREE access to FACTS webinars!
  • Discounts for CME programs
  • Discounts for FACTS enduring materials
  • Professional development and networking opportunities
  • Reduced rates to our conferences (Annual meeting: Nov 9, 2018, Rye Brook, NY)



[i]. John F. Kippley, “A Short History of Natural Family Planning” NFP and More, last modified February 25, 2016, 12. http://www.nfpandmore.org/A%20Short%20History%20of%20Natural%20Family%20Planning%20.pdf
[ii]. R.J. Fehring, M. Schneider, K. Raviele, and M. L. Barron, “Efficacy of Cervical Mucus Observations Plus Electronic Hormonal Fertility Monitoring as a Method of Natural Family Planning,” Journal of Obstetric, Gynecologic, and Neonatal Nursing : JOGNN 36, no. 2 (Mar-Apr, 2007): 152-160.
[iii]. R.J. Fehring, M. Schneider, K. Raviele, D. Rodriguez, and J. Pruszynski, “Randomized Comparison of Two Internet-Supported Fertility-Awareness-Based Methods of Family Planning,” Contraception 88, no. 1 (Jul, 2013): 24-30.
[iv]. R.J. Fehring, M. Schneider, and T. Bouchard, “Effectiveness of an Online Natural Family Planning Program for Breastfeeding Women,” Journal of Obstetric, Gynecologic, and Neonatal Nursing 46, no. 4 (Jul-Aug, 2017): e129-e137.
[v]. R.J. Fehring, and M. Schneider, “Effectiveness of a Natural Family Planning Service Program,” MCN: the American Journal of Maternal Child Nursing 42, no. 1 (Jan/Feb, 2017): 43-49.
[vi]. Fehring, “Effectiveness of a Natural Family Planning Service Program,” 47.
[vii]. Fehring, Schneider, and Bouchard, “Effectiveness of an Online Natural Family Planning Program for Breastfeeding Women,” 129.
[viii]. Meghan Grizzle Fischer, and Pilar Vigil, “White Paper: The Case for FEMM,” FEMM, last modified October 2013. https://femmhealth.org/about-us/white-paper/.
[ix]. M. Arevalo, V. Jennings, and I. Sinai, “Efficacy of a New Method of Family Planning: The Standard Days Method,” Contraception 65, no. 5 (May, 2002): 333-338.
[x]. M. Arevalo, V. Jennings, and I. Sinai, “Efficacy of a New Method of Family Planning: The Standard Days Method,” Contraception 65, no. 5 (May, 2002): 333-338.
[xi]. M. Labbok, V. Hight-Laukaran, A. Peterson, V. Fletcher, H von Hertzen and P Van Look, “Multicenter study of the Lactational Amenorrhea Method (LAM): I. Efficacy, duration, and implications for clinical application,” Contraception 55, no. 6 (Jun 1997): 327-36.
[xii]. A Peterson, R Peŕez-Escamilla, M Labbok, V Hight-Laukaran, H von Hertzen, P Van Look, “Multicenter study of the Lactational Amenorrhea Method (LAM) III: Effectiveness, duration, and satisfaction with reduced client-provider contact,” Contraception 62, no. 5 (Nov 2000): 221-30.
[xiii]. “Discovery and Development of Penicillin,” American Chemical Society, last modified November 5, 2015, accessed March 13, 2018, http://www.acs.org/content/acs/en/education/whatischemistry/landmarks/flemingpenicillin.html.


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