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Are Fertility Awareness Methods Effective for Avoiding Pregnancy?

Are Fertility Awareness Methods Effective for Avoiding Pregnancy?

Jackie Vinyard, M.S. Health Sciences | October 4, 2018 | Avoiding Pregnancy
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For the first 3 years of using hormonal birth control pills, Rebecca had no health concerns to speak of and went about life as normal. A year into her first job post-graduate school, however, she started to experience a handful of issues, including occasional bouts of melancholy and, worst of all, chronic yeast infections.

No amount of medication, exercise, or diet changes seemed to help. Due to the chronic yeast infections that kept coming back each month, she was tested for diabetes and even HIV. She could blame hundreds of variables, from stress to laundry detergent. However, after she changed lifestyle habits and regimen was cleaned up, and these issues still prevailed, she examined her birth control as a last resort.

Rebecca downloaded Kindara the same day she swallowed her last birth control pill in order to track her cycles, mood, and sugar intake. Within 3 months, she was having a regular cycle and no sign of a yeast infection. While she still experienced bouts of melancholy, she found that they correlated directly with her cycle and found ways to manage her mood better through diet and exercise.

Now Rebecca faced a new dilemma: what do to about birth control...

Birth control has revolutionized the workforce and economy. With research showing that the higher the female fertility rate, the lower the chances of paid employment (Reed 1973).  Yet, there is a growing movement amongst women seeking alternatives to what is presently available. (Kounang 2015) Currently, the options for a contraceptive that does not involve invasive devices, surgeries, or interfering with hormones are known as Fertility Awareness Based Methods (FABM) (American Pregnancy Association 2016). FABM is a term that includes all family planning methods that are based on the identification of the fertile window in any given monthly cycle. FABMs, however, are used for much more than just contraception. Women use FABMs to get pregnant, understand hormonal imbalances and what is normal or not, which helps diagnose gynecological problems.

Check out Kindara’s home page and and scroll down to read a few ‘Voices of Kindara’ stories to see how much charting has changed women’s lives.

FABM 101

Natural Family Planning (NFP) and FABM are at times used interchangeably but have one subtle difference: NFP involves sexual abstinence during the fertile time, while FAM involves using the barrier method during the fertile time. For the purpose of this blog, we will be referring to both FAM and NFP as FABM.

Several methods fall under the FABM family. Some of the most common are Billings Ovulation Method, the Creighton Model, and the Symptothermal Method.

Are FABMs effective as a birth control method? Research shows that if used correctly, yes, they can be. The lowest pregnancy rates associated with FABMs are achieved by women who have been properly instructed in how to do so. Many physicians currently are found to not have the proper knowledge to instruct their patients about these methods. Therefore, fertility educators and online communities have been helping women who choose to use this method have a better understanding.

The following methods will be discussed in the blog:

  • Standard Days method or Calendar Method
  • Cervical mucus method (Billings and Creighton Model)
  • Basal body temperature (BBT) method
  • Symptothermal method

Calendar or Standard Days Method


The Standard Days method is similar to the Calendar method in that neither of these methods use any physiological self-observations other than tracking your period. Strict criteria must be met to use this method, including having a regular period, having a cycle length between 26-32 days, and abstaining from intercourse or using another contraceptive method on days 8-19 of your cycle. You will also need to track your cycle for at least 6 months before relying on this method.

How To Do It

For the Calendar method, you can use a period tracking app or manually calculate your estimated fertile days. After figuring out how long your cycles are for 6 cycles, follow these steps to estimate your fertile days:

  1. Use your shortest cycle in your records.
  2. Subtract 18 from the total number of days in that cycle.
  3. Count that number from day 1 of your current cycle and mark with an X. That is your estimated first fertile day.

You learn more about this method here:  (https://www.plannedparenthood.org/learn/birth-control/fertility-awareness/whats-calendar-method-fams).

Risk Level

The risk level when relying on this method to identify your fertile window is high. Ovulation has been found to vary, even in women who have regular cycles (Wilcox). You may ovulate earlier or later than the estimated dates. The American Pregnancy Association says to use this method only as a guide. For contraception, you will need to use this method in combination with other methods mentioned below (APA).   

Cervical Fluid Method


Cervical fluid reveals much more about our bodies than meets the eye because the consistency changes under the influence of rising levels of estrogen. After having a period, women typically experience low levels of estrogen which results in non-wet secretions or what is called ‘dry days’. As estrogen levels rise, the fluid changes to a wetter consistency as she gets closer to ovulation.

This method requires checking your cervical fluid. Cervical fluid is also known as cervical mucus. Here at Kindara, we stick to using fluid instead of mucus simply because it sounds more inviting. While it is technically ‘mucus,’ Toni Weschler had a great point in her book Taking Charge of Your Fertility, “One would never refer to seminal fluid as seminal mucus, and yet the purpose of the fluid in both the man and woman is comparable: to nourish and provide a medium in which the sperm can travel.”

Methods You Can Try

Methods that use cervical fluid to identify the fertile period include the Billings Ovulation method and the Two-Day method.

In the Billings and Creighton Model System methods, you need to monitor your cervical mucus on a daily basis. The appearance and consistency of the cervical mucus changes in relation to your fertility, and specific rules must be followed. For example, when the mucus is wet and stretchy, ovulation typically occurs within one to two days. The Creighton Model System is similar to the Billings Ovulation method, but uses a more precise system and standardized descriptions of cervical fluid.

There is also the Two-Day method You can ask yourself two questions, 1) Do I have cervical mucus today?” and “Did I have cervical mucus yesterday?” IF you answer ‘no’ to both questions the day is assumed safe for unprotected sex (Arvalo 2004). Studies conducted by the World Health Organization indicate that 93% of women, regardless of their education level, are capable of identifying and distinguishing fertile and infertile cervical secretions.


These methods are effective but are even more effective when used in conjunction with the BBT Method.

BBT Method


This method relies on your basal body temperature (BBT) to retrospectively notify you of when ovulations likely occurred. The BBT method requires purchasing a BBT thermometer and taking your temperature the same time every morning before getting out of bed or doing any other activity. You can manually chart your temperatures or use a charting app. When your temperature rises, this indicates that you may have ovulated. The luteinizing hormone surge, which stimulates ovulation, is associated with a 0.5- to 1°F- (0.3- to 0.6°C-) rise in BBT measured with highly standardized methods. BBT remains elevated throughout the luteal phase secondary to higher progesterone levels. The woman is assumed to have ovulated after observing 3 consecutive days of temperature elevation.

How To Do It

BBT can be taken orally, vaginally, or rectally with a sensitive thermometer. Whichever method you chose, the same site should be used daily. For accurate BBT temperature readings, at least 6 hours of uninterrupted sleep the preceding night is necessary. This method is effective if followed as recommended, but it’s only effective for after ovulation. Pregnancy is avoided by abstaining from the beginning of menstruation until 3 to 4 days after the rise in


ACOG states that BBT can show if ovulation has occurred. Studies that examine the effectiveness of BBT to show ovulation are mixed. BBT has been used as an effective way to determine if ovulation has occurred, while others say it is not.

Symptothermal Method

“If you use multiple FAMs together, they work even better.” -Planned Parenthood


The Symptothermal method is a combination of methods and, in the words of Weshler, is “considered the most comprehensive and reliable of all the natural methods because the two primary signs must corroborate each other before you are considered safe.” (Taking Charge of Your Fertility, 20th edition) This method uses BBT method and cervical fluid observation. An additional and optional fertility sign that can be measured in this method is cervical position.


Several studies have been conducted to measure the effectiveness of the method. One paper that looked at high quality clinical studies found this method to have unintended pregnancy rates of <1% with perfect use and 2–8% with typical use.

Pregnancy rates in Europe and India have been reported as low as 1% to 3%. However, unplanned pregnancy rates as high as 13% to 20% have also been reported.

Another more recent study found that if couples used the method consistently and as described (for instance abstaining from intercourse or using the barrier method during the fertile time), a 0.4% pregnancy rate per year was found.


FABM is one of several options available to prevent pregnancy, and we encourage you to explore all your options with a medical professional to find the most effective method that will fit best with you and your lifestyle. For those who desire a more natural solution or cannot tolerate hormones, exciting technological advancements are making this method more user-friendly and accessible. If you decide to use this method or are already using it, keep in mind that condoms are the only method that protects against STDs.

If interested in working with a fertility educator, Kindara users receive 1:1 training and online fertility courses from SymptoPro at a discount. Check it out!




https://www.acog.org/Patients/FAQs/Fertility-Awareness-Based-Methods-of-Family-Planning. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4216977/














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