The Symptothermal, Fertility Awareness-Based Method

The Symptothermal, Fertility Awareness-Based Method

Before the invention of synthetic, lab-made, and perhaps harmful birth control, how did women prevent conception? This question alone is what made me, and millions of other women and menstruators, reconsider their relationship to synthetic birth control and consider all-natural birth control options. In comes FAM.

FAM stands for fertility awareness method, and it is getting a lot of deserved attention right now. It is the practice of learning about your body via your daily biomarkers to determine where you are and aren’t fertile. However, FAM is an umbrella term that encompasses many different types of fertility awareness-based methods (FABMs). Almost always, when someone refers to FAM and its high efficacy rates, they are referring to the symptothermal method, which involves tracking your basal body temperature (BBT), cervical mucus (CM), and cervical position (optional) daily. When done properly, and in combination with a calculation from a previous cycle, this double-check symptothermal method has an efficacy rate of 99.6%.

To learn more about the other types of FABMs, read my blog post here.

So, let’s get into it! 

Our hormones are changing on a day-to-day basis throughout the four phases of our cycle. With these hormonal fluctuations come changes in our mood, metabolism, brain…you name it! Luckily for us, we can track a few crucial biomarkers to guide us into knowing when we are/aren’t fertile. These biomarkers are: BBT, CM, and optional cervical position.


  1. Basal body temperature (BBT): After ovulation, thanks to the production of progesterone from the corpus luteum, your basal body temperature will increase and remain elevated for 10-14 days (the duration of your luteal phase). It will drop back down right before your period OR stay elevated if you have successfully conceived. 
  2. Cervical mucus (CM), also known as cervical fluid: As you approach ovulation, and as your estrogen is rising, you should notice that your CM gets more abundant, however this looks for your unique cervix. In order for sperm to stay alive, transform, and transport to meet your released egg, cervical mucus must be present. In fact, cervical mucus can keep sperm alive for up to five days. Considering that an egg only lives for 12-24 hours, you can only be fertile for 6-7 days each cycle. However you need to confirm ovulation with the rules from your method of choice which typically includes at least 3-4 days of changes in your CM & BBT. After ovulation, when estrogen decreases and progesterone starts to kick in, you will notice that your cervical mucus starts to dry up until your next period. 

cervical mucus and basal body temperature

I love this graphic image from Dr. Mona. Read more on her incredible work here.

The symptothermal method involves tracking each of these biomarkers daily to determine when you are fertile and when you are not. When combined with the calculation method (tracking and referring to previous cycles to get an idea of where you are at within your cycle) it is known as the double-check symptothermal method and is slightly MORE effective than the birth control pill. 

Birth control pill efficacy:

  • Typical use: about 91%. Perfect use: about 99% effective.

Symptothermal method efficacy:

  • Typical use: 98-99%.
  • Perfect use & double-check: 99.6%

So, it seems like the symptothermal method of FAM is a win all around: no side effects, a deep understanding and love for your body and cycle, and effective at preventing (or achieving if desired) conception.

I highly recommend working 1-1 with a FAM instructor at the beginning of your journey, even if it is just one session. Invest in yourself… in your health… and in your future. 

*A note on apps: Don’t rely on an app’s algorithm to tell you when you are or aren’t fertile. Instead, turn off the prediction functionality and just use the app to keep track of your biomarkers, symptoms, etc.. OR, you may download my printable trackers and log everything in the traditional way, via pen to paper. :-)

Are you ready to learn how to use the symptothermal FAM? Click here and use code MADDIE10 to save on all FAM offerings with Dr. Mona.


  1. Effectiveness of Fertility Awareness-Based Methods for Pregnancy Prevention: A Systematic Review, 2018
  2. Frank-Herrmann P, Heil J, Gnoth C, Toledo E, Baur S, Pyper C, Jenetzky E, Strowitzki T, Freundl G. 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 May;22(5):1310-9. doi: 10.1093/humrep/dem003. Epub 2007 Feb 20. PMID: 17314078.
  3. Oliver R, Pillarisetty LS. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Nov 3, 2020. Anatomy, Abdomen and Pelvis, Ovary Corpus Luteum. [PubMed]
  4. Steward, K., & Raja, A. (2022). Physiology, Ovulation And Basal Body Temperature. Retrieved 5 July 2022, from 
  5. Wiggins, M. (2022). Types of FABMs: What are they & how do they work?” — Medicine with Mona. Retrieved 5 July 2022, from 
  6. Fertility awareness-based methods of family planning: A review of effectiveness for avoiding pregnancy using SORT, 2013
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