If you’ve recently been living under a rock, you might have missed the news about the first FDA-cleared birth control app that purports to allow you to prevent pregnancy by telling you when you are safe for unprotected intercourse. I’m loath to mention its name, however, for fear that women will run out and download it without understanding its most serious pitfall, which I will get to in a minute.

As I mentioned a couple years ago, when I first decided to publish Taking Charge of Your Fertility back in the Paleolithic Era of 1995, the internet had yet to dominate our lives. So back then, the thing that kept me up nights was my concern that women would maybe misunderstand concepts in the book, leading to unplanned pregnancies.

Today, those fears seem almost quaint compared to a much bigger concern: the pervasiveness of scores of bogus apps, all of which claim to be able to predict a woman’s fertility based on nothing more than inputting the first day of a period (typically referred to as Period Trackers or Ovulation Calculators) or by tracking your BBT, such as the newly cleared app referred to above. In fairness, the BBT-focused apps will accurately tell you when you are very likely safe for unprotected intercourse after ovulation. But one of the huge drawbacks of these Period Tracking and BBT apps is that they claim to be able to predict upcoming preovulatory fertility using an algorithm based on past cycles . . . which is nothing more than a high-tech version of the obsolete Rhythm Method.

In order to judge whether an app is reliable across the entire menstrual cycle (both before and after ovulation), at a minimum it should allow you to input your cervical fluid in addition to basal body temperature, as well as other secondary fertility signs such as ovulatory pain. Those that only include temps cannot indicate when ovulation is about to occur, but only confirm if ovulation has already happened. To know on a daily basis whether or not you are fertile, you need to observe and record your cervical fluid, which is critical when you are trying to get pregnant, and the stakes are even higher when you are trying to prevent pregnancy.

Before even considering using one of these apps to prevent pregnancy, I encourage you to thoroughly read my book or better yet, also take a class in the Fertility Awareness Method, because the apps alone can’t possibly provide you with the instruction and personal counseling necessary to be able to understand how to rely on your primary fertility signs.


The first link below lists secular instructors, and the last link includes religious instructors, which you may or may not appreciate.



Apps are certainly not a replacement for proper education about your body and fertility, and regardless, as the technology stands now, they should never be used as a sole method of birth control. As proud as I am of my own app, OvaGraph, which was designed to mirror the pencil and paper charting methods outlined in my book, even I admit that this app should only be relied on for determining your fertile days when you are trying to get pregnant. And while it incorporates all of the Fertility Awareness Method principles —including charting cervical fluid along with BBT—many women who are trying to conceive choose to also use additional ovulation prediction tools along with charting at OvaGraph. But, if you are trying to prevent pregnancy, the app should be used only as a convenient way to always have your charts with you, and even to share them with a clinician or others.