Research suggests period tracking apps aren’t as reliable as you think

The medical app industry has exploded in the past decade, with over 40,000 applications now in circulation. Over a thousand apps allow women to track their menstruation cycles and can be used to either avoid or achieve pregnancy. The apps are an incredibly convenient way to track fertility biomarkers.

Period apps tend to fall into two major categories: ones that are calendar based and allow users to plugin their period start and end point, and ones that are symptom-thermal and are based on physical signs of ovulation such as cervical mucus or basal body temperature.

Apps like Kindara and Yono sync with thermometers, while apps like Ava collect data as users sleep, measuring things such as skin temperature and blood flow. Natural Cycles combines calendar and temperature information, and is FDA certified.

All in all, the aim of all these apps is to identify the user’s fertility window, the 6 days in which they can conceive.

However, not all apps use evidence-based fertility awareness -based methods (FABMs), whose rates of efficacy mirror common forms of hormonal birth control. Achieving and preventing pregnancy are both important responsibilities, so its of the utmost importance that the apps women access can reliably track their fertility.

Thus far, research into these apps’ efficacy has been primarily based on preventing pregnancies, since the stakes are much higher. However, there has not been enough empirical evidence to suggest that users should trust the app to calculate when they are fertile.

A study from Georgetown university looked into these apps and their findings addresses these concerns. The study’s researchers examined 30 apps that predicted female fertility timings, and found 24 to have misclassified fertile days as infertile. Marguerite Duane M.D, lead author on the study, concluded from her findings that women must be cautious when using these applications.

“While an app can be a wonderful way for a woman to track her data, she shouldn’t rely on it to tell her when she may be fertile,” she says.

According to Eve Feinberg M.D, VP of the Society for Reproductive Endocrinology and Infertility, these apps tend to a provide women with a feeling of empowerment, even though their pregnancy tracking methods usually do not offer anything more than traditional tracking methods.

Dr. Feinberg explains that the majority of couples conceive over the course of a year, and that past periods are a reliable predictor of ovulation. It is instrumental for women with regular period cycles to have sex on days 10, 12 and 14, while those with irregular menstruation cycles should try every day after their period.

“It shouldn’t be that hard to hit the window when the egg is released. It’s not rocket science,” he says.

Unlike most fertility apps, these traditional pregnancy-tracking methods are free. Users can pay up to $1.99 a month and over USD$200 for wearables. The market for “femtech” (female technology focused on reproductive health) is growing at a rapid pace, and is estimated to be worth over USD$50 billion by the year 2025.

Although most scientists postulate that women should use any approach that works for them, researches suggest that women should rely more on their body signs than any man-made app.