Familiarizing yourself with fertility awareness as a birth control option

Contemporary OB/GYN JournalVol 65 No 06
Volume 65
Issue 06

Behavioral methods of contraception are used by less than 3.2% of sexually active women; careful counseling could change that.


Fertility awareness-based contraceptive methods (FABM) are behavioral methods of contraception that are used by approximately 2.2% to 3.2% of sexually active women.1 This low usage rate may be due to provider and patient knowledge and beliefs. One concern providers may have is that the typical use efficacy rate is lower than for other contraceptive methods. In addition, providers may be uncomfortablen counseling patients about appropriate usage.2

Women who use FABM may choose it because they have values and/or beliefs that are aligned with using non-pharmacologic contraception. However, we must consider that the best form of contraception is the one the patient feels works for her. Given that FABM may be used as a contraceptive, and that there are patients who will choose it, ob/gyns must be familiar with it and ready to counsel about its use.


Nonjudgmental and open conversation with patients about their priorities is critical to all contraceptive counseling, particularly when discussing FABM. Generally, FABM is most suitable for patients who have regular menses (although some methods, such as TwoDay®, may not require this) and for whom variance in efficacy of a method-and therefore the real possibility of an unplanned pregnancy-is acceptable.

As such, an important part of counseling is reviewing medical comorbidities, obstetric history, and current medications so that the patient understands the risks of unplanned pregnancy to their health and the health of the fetus. Given that FABM requires abstinence or use of barrier methods on certain days, the ability to have open communication with a partner is paramount. Considering this, FABM may work best for patients whose partner(s) is highly motivated to avoid pregnancy and willing to avoid unprotected sex on certain days.

Thirty-six percent of women in the United States suffer sexual violence and coercion3; behavioral methods cannot protect against pregnancy in these cases. In addition, FABM does not offer protection against sexually transmitted infections.

It is important to note that studies of FABM effectiveness vary in quality, which makes it difficult to compare efficacy between specific methods.4 Overall, FABM collectively has a 15% typical-use first-year failure rate, but it can vary as much as 2% to 23%.5-7 There are many factors that impact effectiveness of FABM.

These include the ability of the provider to adequately counsel on how to use the method and the ability of the patient to follow and use the method instructions appropriately.6 Given that most studies show high first-year discontinuation rates for FABM,4 shared decision-making and clear instructions on how to properly use each technique are critical to successful patient use. Table 1 summarizes the methods and key requirements for each method.6,8-20

Patients who choose FABM over other methods are likely doing so for reasons beyond its efficacy. It is well-studied that contraceptive counseling and recommendations should be patient-centered.9 If a patient is aware that FABM has variable efficacy rates, has been counseled on the factors that make a good FABM candidate, and accepts the risk of unintended pregnancy, there is no reason a clinician should be uncomfortable with aiding her in using that method.  

Advantages to FABM include little to no financial investment, few if any medical contraindications to use, no medications or devices needed, and possible alliance with religious and cultural beliefs about family planning.

In addition, many patients may choose to educate themselves about and use behavioral methods in the time leading up to planning a pregnancy. This is because these methods require more awareness of the body and the fertile time, which helps a patient to prevent pregnancy and also to become pregnant when she is ready.

Avoiding fertilization

The crux of FABM is understanding the menstrual cycle and using biological knowledge and cues to predict when fertilization is most likely.4,5,21 We know that ovulation most often occurs in the middle of a menstrual cycle; given that sperm can persist for 3 to 5 days in the female reproductive tract and the ovum has a lifespan of 12 to 24 hours, the fertile window lasts for approximately 6 days.5,7,8,17,21

In cycles with lengths of 26 to 32 days, 78% of women will have a fertile window between Days 8 and 21.17 There are various methods that can be used to predict the fertility window-and therefore the period of “at-risk” days for pregnancy-during a menstrual cycle.

In addition to counseling patients how to predict these days, it is vital to discuss how they will avoid unprotected intercourse during the 10 to 17 “at-risk” days of their menstrual cycle.6 If they are interested in barrier methods (condom, diaphragm), ensuring proper instruction on how to use them is needed to ensure effectiveness of FABM.6


Elena is a 28-year-old G0 who is considering pregnancy in the next 1 to 2 years. She and her husband prefer a method that does not involve exogenous hormones or medical devices. She asks you about using a fertility awareness-based method (FABM) for contraception She has tracked her regular periods for many years and is detail-oriented. Elena has no medical problems and takes a multivitamin daily.

Which of the following do you tell her is important to the success of using an FABM method?

A. Meticulous, daily recording

B. Ability to avoid unprotected intercourse

C. Adequate knowledge about how to determine “at-risk” days

D.  All of the above

Answer: D. All of the above

Patients are most likely to have success using FABM if they are able and committed to meticulous, daily attention and recording of various aspects of their cycle (depends on what method), able to avoid unprotected intercourse, and are well-informed about the specific method they are using.

For these reasons, we recommend the Standard Days® (CycleBeads®) method or the TwoDay® method, as they are the most straightforward methods for providers and patients.

The Standard Days Method® requires 6 months of menstrual cycle tracking prior to initiation. It requires that a menstrual cycle is between 26 and 32 days long. Patients who are breastfeeding or who have recently stopped hormonal contraception may not have anticipated efficacy with this method and should wait to observe their cycles before starting.

The Standard Days Method® relies on the fact that unprotected intercourse has a low likelihood of causing pregnancy on menstrual cycle Days 1 to 7 and from Day 20 until the end of the cycle. The patient should abstain from intercourse or use a barrier method on Days 8 to 19.

Cyclebeads® are a helpful way for a patient and her partner to keep track of cycles together; bead colors may indicate fertile and less fertile days, so they know when unprotected intercourse will avoid pregnancy. She can place the beads in a common area as a way to communicate with her partner. With perfect use, this method is 95% effective and with typical use, it is 88% effective.

The TwoDay Method® relies on a patient’s comfort, awareness, and tracking of vaginal secretions and on the fact that thin, watery, secretions make it possible for sperm to travel through the female reproductive tract and survive for several days.

The cervical fluid around the time of ovulation is particularly characteristic in that it is abundant, clear, and stretchy.15,18 Therefore, when a patient is dry or lacks vaginal secretions, it has been theorized she is less likely to become pregnant. A patient may use touch to assess for secretions, or observe them on underwear or a menstrual pad. If she does not experience vaginal secretions for 2 days in a row, the risk of pregnancy is low.

Patients should abstain from or use barrier methods for 3 days following unprotected intercourse, as the ejaculate interferes with the ability to assess for presence of vaginal secretions. Benefits of this method are that it can be used by women who have irregular cycles and that it is simple to understand and execute.

Patients should be warned that vaginal infections can interfere with symptom assessment. With perfect use, the TwoDay Method® is 97.5% effective, and with typical use, it is 86% effective.

For Elena, we can counsel her that both of these methods have similar perfect and typical use, are easy to understand, can help her prevent pregnancy for now, and can aid in achieving pregnancy in the future.

Educating her about the Standard Days Method® may provide her with more information about ovulation and a fertile window, while the TwoDay Method® can inform her about the role of cervical mucous in fertility. Ultimately, we can discuss which method she feels most comfortable with and provide her with supplemental reading material.


The world of contraception is constantly changing, with improving technologies, new devices, and more options than ever before. In addition to staying up to date within the evolving field of Family Planning, ob/gyns should also be prepared to counsel and support patients who choose to use FABM.

These methods require an ob/gyn to be knowledgeable about it and able to engage in shared decision-making with the patient to determine which method is appropriate. There are many resources ob/gyns can use to refresh their knowledge about these methods-many of which are cited in this review.

We feel the Standard Days Method® (CycleBeads®) and TwoDay Method® are the simplest to use and counsel about and the easiest for patients to understand. With proper counseling and education, FABM may be a satisfactory option for your patient.


1. Polis CB, Jones RK. Multiple contraceptive method use and prevalence of fertility awareness based method use in the United States, 2013-2015. Contraception. 2018;98(3):188-192.

2. Lawrence RE, Rasinski KA, Yoon JD, Curlin FA. Obstetrician-gynecologists' views on contraception and natural family planning: a national survey. Am J Obstet Gynecol. 2011;204(2):124 e121-127.

3. Smith SG, Zhang X, Kathleen C. Basile, et al. National Intimate Partner and Sexual Violence Survey: 2015 Data Brief-Update Release. [National Center for Injury Prevention and Control and Centers for Disease Control and Prevention]. 2018; https://www.cdc.gov/violenceprevention/pdf/2015data-brief508.pdf. Accessed January 21, 2020.

4. Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby. N Engl J Med. 1995;333(23):1517-1521.

5. Arévalo M, Sinai I, Jennings V. A fixed formula to define the fertile window of the menstrual cycle as the basis of a simple method of natural family planning. Contraception. 1999;60(6):357-360.

6. Nelson AL, Sokol DC. Behavioral Methods of Contraception. In: Jensen JT, Creinin MD, eds. Speroff & Darney’s Clinical Guide to Contraception. 6th ed. Philadelphia, PA: Wolters Kluwer; 2020.

7. Peragallo Urrutia R, Polis CB, Jensen ET, Greene ME, Kennedy E, Stanford JB. Effectiveness of Fertility Awareness-Based Methods for Pregnancy Prevention: A Systematic Review. Obstet Gynecol. 2018;132(3):591-604

8. Hatcher RA, Kowal D, Nelson AL, et al, eds. Contraceptive Technology. 21st ed. Atlanta, GA: Managing Contraception, LLC; 2018.

9. Kambic RT, Lamprecht V. Calendar rhythm efficacy: a review. Adv Contracept. 1996;12(2):123-128.

10. Trussell J, Grummer-Strawn L. Contraceptive failure of the ovulation method of periodic abstinence. Fam Plann Perspect. 1990;22(2):65-75.

11. Wilcox AJ, Dunson D, Baird DD. The timing of the "fertile window" in the menstrual cycle: day specific estimates from a prospective study. BMJ. 2000;321(7271):1259-1262.

12. Frank-Herrmann 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. Adv Contracept. 1997;13(2-3):179-189.

13. Arévalo M, Jennings V, Sinai I. Efficacy of a new method of family planning: the Standard Days Method. Contraception. 2002;65(5):333-338.

14. Freundl G, Sivin I, Batar I. State-of-the-art of non-hormonal methods of contraception: IV. Natural family planning. Eur J Contracept Reprod Health Care. 2010;15(2):113-123.

15. Bhargava H, Bhatia JC, Ramachandran L, Rohatgi P, Sinha A. Field trial of billings ovulation method of natural family planning. Contraception. 1996;53(2):69-74.

16. A prospective multicentre trial of the ovulation method of natural family planning. II. The effectiveness phase. Fertil Steril. 1981;36(5):591-598.

17. Grimes DA, Gallo MF, Grigorieva V, Nanda K, Schulz KF. Fertility awareness-based methods for contraception. Cochrane Database Syst Rev. 2004(4):CD004860.

18. Arévalo M, Jennings V, Nikula M, Sinai I. Efficacy of the new TwoDay Method of family planning. Fertil Steril. 2004;82(4):885-892.

19. Frank-Herrmann P, Freundl G, Baur S, et al. Effectiveness and acceptibility of the symptothermal method of natural family planning in Germany. Am J Obstet Gynecol. 1991;165(6 Pt 2):2052-2054.

20. Frank-Herrmann 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 behaviour during the fertile time: a prospective longitudinal study. Hum Reprod. 2007;22(5):1310-1319.

21. Lamprecht VM, Grummer-Strawn L. Development of new formulas to identify the fertile time of the menstrual cycle. Contraception. 1996;54(6):339-343.

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