August 26, 2020

Editor’s Note: National Breastfeeding Month is the perfect time to recall the many benefits of breastfeeding for both mother and child. One of these benefits is built directly into a woman’s normal physiology and provides safe, effective natural family planning for six months postpartum as long as the new mother chooses to breastfeed exclusively and her menses has not yet returned. The postpartum inhibition of ovulation provided by such exclusive breastfeeding is the foundation for the lactational amenorrhea method (LAM) of family planning; you can learn more about this well-researched method HERE.

Although the lactational amenorrhea method has been around for more than thirty years, its benefits are not nearly maximized in our society due to a lack of education and knowledge about its effectiveness and benefits. This week’s article is a summary of a research study by Valdés et al titled, “The efficacy of the lactational amenorrhea method (LAM) among working women.”[i] Its year of publication (more than two decades ago!) highlights how long we’ve had evidence of the effectiveness of this fertility awareness-based method (FABM).

A fourth-year medical student who is now pursuing residency in obstetrics and gynecology wrote this review during the FACTS online elective offered through Georgetown University School of Medicine. To learn more about this and our new elective, Fertility Awareness for Women’s Health, please visit our website. Our cohorts are filling up, so reserve your spot soon! Our virtual conference on modern fertility awareness for women’s health and family planning will include lectures about breastfeeding and LAM as well. Learn more about the October 2-3, 2020 FACTS Virtual Conference and register HERE.


For years, it has been well known that the lactational amenorrhea method of family planning is highly effective in preventing pregnancy postpartum. The effectiveness rate to avoid pregnancy among women who follow LAM strictly is 98% during the first 6 months of the postpartum period. This high efficacy relies on the new mothers exclusively breastfeeding their infants around the clock with no manual expression or pumping of breastmilk. With more mothers returning to work early in the postpartum period, what happens to the efficacy of LAM? Even decades after its publication, this study of a modification of LAM offers insights and recommendations that are perhaps even more relevant now than when it first published.


Valdés et al studied urban, middle-class working women who desired to use LAM and also returned to work prior to 120 days postpartum. Between March 1992 and July 1993, women were recruited both in the immediate postpartum period after delivery and at the time of the 30-day postpartum follow up visit at a university hospital. Women recruited immediately postpartum were entered into the study only if they planned to exclusively breastfeed and follow LAM. New mothers recruited at the 30-day follow up were entered only if they had been exclusively breastfeeding up to that point, with no return of menses, and planned on utilizing LAM as their method of natural family planning. 

Each new mother enrolled in the study received individualized counseling on how to continue breastmilk feedings upon her return to work. They were all educated on LAM and taught how to express their breastmilk manually. Participants were instructed to breastfeed their infants when they were home and to manually express and store breastmilk every four hours when at work and away from their infants. Information and resources were provided so each woman knew who to contact if facing difficulties at any point during the study period.

All participants were required to undergo pregnancy tests every month after returning to work, at the end of the 6-month postpartum period, and at 12 months postpartum. They were also required to strictly follow LAM, so the women were expected to feed their infants breastmilk exclusively for the duration of the 6-month postpartum period.


The study included 170 urban, middle-class working women who planned on using LAM but also had to return to work prior to 120 days postpartum. Women involved in the study returned to work after an average of 92 days postpartum. Before returning to work, no pregnancies occurred among the mothers using LAM. A total of 3 women became pregnant by the end of the study: one at 4 months, one at 5 months, and one at 6 months postpartum after returning to work. The cumulative risk of pregnancy by the end of the 6-month postpartum period was 5.2%.


LAM has been proven to be extremely efficacious, with a pregnancy rate of 2% among mothers who are able to follow LAM strictly. However, in this study, LAM was found to have a decreased efficacy among women who use this method but return to work, with a cumulative risk of pregnancy for that subgroup of 5.2%. Among women using LAM, this study suggests that returning to work can decrease the method’s efficacy. Therefore, women who desire to use LAM but plan on returning to work should be thoroughly informed of this finding. Future trials with a larger and more diverse study group should be performed.

Editor’s Note: The lactational amenorrhea method has a perfect-use effectiveness rate of 98%, which is comparable to and better than some of the currently available methods of birth control. This study reveals the importance of educating women about all available options for family planning during their pregnancy and in the postpartum period. For women interested in natural or fertility awareness-based methods of family planning, they may choose the method that works best for them based on their goals and lifestyle, learn how to use it, and transition from LAM to that method prior to returning to work. Working with a trained instructor during these transitions is vital to ensure the woman and couple have the knowledge and resources needed to use each method successfully.

For more research reviews and articles about breastfeeding and fertility awareness-based methods, click HERE.


[i] Valdés V, Labbok MH, Pugin E, Perez A. The efficacy of the lactational amenorrhea method (LAM) among working women. Contraception. 2000;62(5):217-9.


2020 Back-to-School Fundraising Campaign

August 17-31

Our BTS Fundraising Campaign kicks off next week and we invite you to join us!  Our robust programming couldn’t exist without your support. Your partnership is essential to the FACTS mission as we work to fill the gap in medical education about evidence-based, natural or fertility awareness-based methods (FABMs).

Donate TODAY or stay tuned for more information on how you can help FACTS build better healthcare for all women!

FACTS 2-Day Virtual CME Conference
October 2-3, 2020

Modern Fertility Awareness for Women’s Health and Family Planning

After careful consideration, we have decided to postpone our one-day CME conference originally planned for July 11, 2020 in Baltimore, MD. The GOOD NEWS is we have changed the conference to a completely digital format and moved the dates to Friday, October 2 and Saturday October 3, 2020. We are looking forward to this event as an opportunity to connect with one another, learn more about fertility awareness, and to share all we have accomplished together.

As interest in FABMs increases, it is important that YOU are well-equipped with the latest research to inform women. Join us to expand your toolbox and be better prepared to counsel women about FABMs so they may make more informed healthcare choices. Learn more and register today!

We hope to “see” you there!

Are you a Physician or Fertility Educator trained in FABMs?
Patients are searching to find you!

FACTS is compiling a searchable, national database of physicians, medical professionals, and fertility educators to serve as an important resource for patients and the medical community. We hope you will join us! Click here to enter your practice information or email us for more information.

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