When I first started learning about Fertility Awareness Methods (FAM) back in 2011, there were very few FAM based apps to be found. The apps that did exist were designed with the goal of achieving pregnancy rather than preventing it. Yes, there were web apps such as Fertility Friend (again, designed with the goal of achieving pregnancy) for use on desktop and laptop computers, and there was standalone technology such as the LadyComp. However, the LadyComp was, and still is, prohibitively expensive for most people at nearly $450 USD. On top of this, at that time there were very few budget friendly tablets on the market and less than 45% of American adults owned smartphones, so even if an effective birth control app had existed, many menstruating humans would’ve had no device to use it on. Today, on the other hand, there are multiple birth control apps available (both free and paid), tablets have become more affordable and 77% of American adults own a smartphone – making this an option easily accessible for most people who get periods.
Recently, Natural Cycles became the very first birth control app to receive government approval as a certified medical device. The creators of Natural Cycles, Swedish physicists/couple Elina Berglund and Raoul Scherwizl, performed a study of over 4,000 people aged 20-35 years old using the app. They determined that with typical use of the Natural Cycles app, seven out of 100 menstruating humans would become pregnant, and with perfect use five out of 1,000 people who get periods would become pregnant. This is very similar to birth control pills with Natural Cycles being 2% better with typical use, and 0.2% worse with perfect use.
The user instructions for Natural Cycles are simple: Take your temperature upon waking in the morning with a basal body temperature thermometer (purchased separately or included with the app for a fee), and enter the number into the app. The app then calculates whether or not you’re fertile using its algorithm and will give you a red (use a barrier method or abstain) or green indicator (no need to use protection). As with any contraceptive method other than condoms, the app doesn’t protect against STIs.
Natural Cycles is based, at least partially, on the Fertility Awareness Method. If you’re not familiar with it, FAM is a set of rules that, if followed correctly and consistently, can be used to either avoid or achieve pregnancy. FAM is also an excellent tool for identifying hormone imbalances and thyroid issues.
To summarize the rules of FAM: Firstly, a menstruating human is only fertile for up to six days per cycle. They can generally consider themselves infertile for the first five days of their cycle, which begins with the first day of bleeding. This rule only applies if they’ve confirmed ovulation 12-16 days prior to the beginning of their current cycle and if they’ve never had a cycle less than 25 days long. Ovulation can be identified by an upward temperature shift of at least 0.2 degrees sustained for three or more days. Once ovulation has been confirmed, it’s safe to have unprotected sex without the risk of getting pregnant up until the end of the first five days of the following cycle.
“FAM is a set of rules that, if followed correctly and consistently, can be used to either avoid or achieve pregnancy.”
Before using FAM or any FAM based app as birth control, I strongly recommend you either read a book such as Taking Charge of Your Fertility or take a course on Fertility Awareness methods. This way, you can familiarize yourself with the different types of cervical fluid and what they mean, as well as go into more depth about the method and how to use it effectively.
The more rules you follow, the more effective FAM is and the fewer days you have to use barrier methods or abstain from sex. If you don’t follow all of these rules, the method becomes less effective at preventing pregnancy. I’ve personally been using the Sympto-thermal Fertility Awareness Method as my primary form of birth control since I had my copper IUD removed a little over a year ago. I also practiced charting my cycles with FAM throughout the five years that I had my IUD. All in all, it’s a great method of birth control for me. If I’m ever unsure or think that my temperatures have been unreliable due to illness or poor sleep, I consider myself possibly fertile and make sure to use a barrier method.
As far as the Natural Cycles app is concerned, its algorithm relies on basal body temperature fluctuations with the option of supplemental ovulation predictor tests. It doesn’t, however, take into account cervical fluid and therefore isn’t appropriate for those with very long, very short or irregular cycles, such as breastfeeding people or humans with Polycystic Ovarian Syndrome. The study used to determine the failure rate of Natural Cycles included only those between 20 and 35 years of age. This means that there’s a possibility that the app won’t be as effective for menstruating humans outside of this age range. People who get periods and are coming off of hormonal birth control of any kind, including the pill, the Mirena IUD, implant or Depo Provera shot should also not rely on the app, as the algorithm used won’t be able to accurately predict when you’re fertile and when you’re not. To put it very simply, this app is likely to be most effective for those with very regular cycles that are neither too long nor too short and who are within the age range used in the study.
Birth control is a personal choice, and you should use whatever method works best for you. If you do decide to look further into the FAM method, remember that the more FAM rules you follow, the more effective it is at preventing pregnancy. When in doubt, use a barrier method or abstain.
Published in the Winter 2018 Issue. Get a digital or print copy here.