January 20, 2025

The Role of Fertility Awareness-Based Methods Postpartum: A Research Review

By: Kristie Jones Robles

Editor’s Note: Evidence-based fertility awareness-based methods (FABMs) have decades of research behind them to support their effectiveness to avoid pregnancy. Some of them go an extra step to provide evidence supporting their use during unique circumstances such as breastfeeding and postpartum. The efficacy study [1] summarized below has provided such peace of mind for women in the postpartum phase since its publication in 2012 in Contraception by Sinai and Cachan. Kristie Jones Robles summarized the article while on the FACTS online elective that has educated hundreds of students since 2018. The course is also available for residents and as CME for other medical and health professionals. Join one of our courses and let FACTS equip you with accurate information and practical tools to support your patients!

Introduction

The postpartum phase comes with a variety of exciting and complex changes. If a woman previously used fertility awareness-based methods (FABMs), the physical changes that occur during pregnancy and after giving birth can make it uniquely challenging to begin or resume FABMs. For a breastfeeding mother in particular, the return of her menstrual cycle can vary greatly. Once menses does return, her cycle length can be unpredictable. Ovulation becomes more difficult to predict and usually occurs later in the cycle compared to the woman’s typical cycle. This can lead to higher rates of unintended pregnancy.

“The physical changes that occur during pregnancy and after giving birth can make it uniquely challenging to begin or resume FABMs.”

The Standard Days Method is a well-established FABM that provides a simple yet effective approach. It is a calendar-based method that establishes a fixed fertile time in a woman’s cycle, days 8 through 19. If the couple is aiming to avoid pregnancy, they are advised to refrain from sexual intercourse during this fertile window. This method is most effective for women who have cycles between 26 to 32 days long.

Due to the variability and long cycle lengths during the postpartum phase, it can be challenging for a woman to use the Standard Days Method to avoid pregnancy. To address this, Sinai and Cachan conducted the research published in 2012 titled, “A Bridge for Postpartum Women to Standard Days Method® II. Efficacy study.” It is the efficacy study of a previously described new fertility awareness-based Bridge for postpartum women until they are eligible for the Standard Days Method. [1] [2]

The Bridge is appropriate for women who have had at least one menses postpartum. Each woman who uses the Bridge is counseled to avoid sexual intercourse from day 11 through the end of the first cycle. Once Cycle 2 begins, she should avoid intercourse from day 8 through 24. She will continue to avoid intercourse on days 8 to 24 for subsequent cycles (Cycle 2+) until the cycles return to a length that is eligible for the Standard Days Method.

“Each woman who uses the Bridge is counseled to avoid sexual intercourse from day 11 through the end of the first cycle. Once Cycle 2 begins, she should avoid intercourse from day 8 through 24.”

Methodology

The prospective, nonrandomized, multicenter study followed 157 women ages 18 to 39 for up to 9 months. Participants wished to avoid pregnancy using an FABM. The women were seen in two sites across two countries, Perú and Guatemala, and counseled through existing programs. All the participants were no longer eligible to use the Lactational Amenorrhea Method (LAM) but were interested in the Standard Days Method, though not yet eligible to use it.

Participants were interviewed monthly during Cycle 1, every two weeks during Cycle 2+, and when they became eligible to use the Standard Days Method and stop the Bridge. Each participant was also asked to keep a daily coital log.

The researchers analyzed correct-use and acceptability. Life table pregnancy rates were used to assess method effectiveness.

Results

In total, there were 17 pregnancies: seven in Cycle 1 and ten in Cycle 2+. Nine of the pregnancies were reported in Perú and eight in Guatemala. Four of these pregnancies resulted from method failure, where the participant used the Bridge instructions correctly. The correct-use and typical-use pregnancy rate for the Bridge for 6 months was 3.72% and 11.2%, respectively.

Discussion

This efficacy study demonstrates that the Bridge significantly prevents unintended pregnancy. The correct-use pregnancy rate of 3.72% for 6 months is similar to the correct-use pregnancy rate of 3.51% for the Standard Days Method. [3] Nevertheless, the typical-use pregnancy rate for the Bridge, 11.2%, was higher compared to the Standard Days Method, 9.3%. [3] These pregnancies can most likely be attributed to user failure, where participants had intercourse during the fertile days.

The Bridge is an effective transition to the Standard Days Method for women who wish to use an FABM in the postpartum period. Users appreciate that it is side effect-free, easy to learn and use, and effective in avoiding pregnancy. It is reassuring that new techniques are being developed that are consistent, easy to understand, and effective for women to use during the postpartum period, where there are increasing levels of fertility yet irregular ovulation. Some of the advantages of the Bridge are its simplicity and low cost, which makes it appealing for underserved populations that lack access to a variety of resources and are unable to have the extensive teaching other FAMBs require.

“The Bridge is an effective transition to the Standard Days Method for women who wish to use an FABM in the postpartum period. Users appreciate that it is side effect-free, easy to learn and use, and effective in avoiding pregnancy.”

Since the return of menses is one of the requirements to use the Bridge, women with persistent amenorrhea postpartum cannot use the Bridge. If a woman can no longer use the Lactational Amenorrhea Method, either because she is not meeting the minimum breastfeeding requirement or her infant is more than six months old, she will need to find another method to avoid pregnancy. While some FABMs (e.g. mucus-only methods and hormonal monitor device methods) have been described for women to use postpartum, further research on the postpartum phase is needed to offer women a variety of easy-to-use, effective fertility awareness-based approaches to avoid pregnancy.

References

[1] Sinai I, Cachan J. A Bridge for postpartum women to Standard Days Method® II. Efficacy study. Contraception 2012; 86:16–21.

[2] Sinai I, Cachan J. A Bridge for postpartum women to Standard Days Method® I. Developing the Bridge. Contraception 2012; 86: 12–5.

[3] Arévalo M, Jennings V, Sinai I. Efficacy of a new method of family planning: the Standard Days Method. Contraception 2002; 65: 333–8.

ABOUT THE AUTHOR

Kristie Jones Robles

A fourth-year medical student at Ponce Health Sciences University School of Medicine in Puerto Rico, Kristie Jones Robles has demonstrated a commitment to diversity and service. She earned a BA in psychology with a minor in chemistry at Old Dominion University and plans to complete residency training in pediatrics. Throughout her career, she envisions providing compassionate care to a diverse population in areas with a crucial need for medical professionals. She completed the FACTS elective to develop a better understanding of FABMs and effective methods to educate patients and manage a variety of women’s health conditions.

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