Do fertility apps really work?

Fertility apps promise to act as a natural contraceptive and a safe alternative to the pill. But are they actually effective?

fertility apps, Daysy, pregnancy, birth control
Image: Muses Uniform

Nowadays, there’s an app for everything — meditation, healthy recipes, and even baby-making. Yep, a quick search of keywords like “period” or “fertility” in the app store reveals dozens of results that could help you fall pregnant — or avoid it, depending on your goal. Not to mention, apps that help you track your menstrual cycles. Considering this, it’s not uncommon for women to then interpret this data to follow the rhythm method (also known as the calendar method), a natural way to avoid getting pregnant while also avoiding the pill.

How does it work?

The rhythm method assumes that sex on certain days, such as the week of your period, won’t lead to pregnancy. Sex during these infertile times is often also accompanied by the pullout method. By tracking body temperature and ovulation, and storing this information on their phones, women also know when they’re most fertile (usually 14 days before a women’s period, or in the middle of a 28-day cycle) and avoid unprotected sex during those times if they don’t want to conceive.

There’s even some research to suggest this method could be effective. According to a 2009 study of the pullout method, compared with typical condom use, the former is only slightly more likely to result in pregnancy.

Is there an app?

One popular app that doesn’t shy away from its claims to help prevent pregnancy is Daysy. The program comes with a thermometer that plugs into a smartphone to share data. After taking your temperature daily and tracking your period, Daysy claims to determine ovulation and fertility with an accuracy of 99.3% using easy color-coding. If you’re in the red zone you are fertile, the green zone represents a not fertile day, and orange is undecided.

fertility apps, pregnancy, birth control, Daysy
Image: Daysy

“Daysy learns the woman’s cycle as it carefully monitors temperature each day. This allows the device to get clued up on the ebbs and flows and hormonal changes, allowing it to show a woman when she is in the fertile time of her cycle and when she is not,” a Daysy spokesperson told us, adding that for women who are looking to avoid the long-term side-effects of synthetic hormones or who are keen to understand their cycles better, this device is a game changer.

What are the cons?

Despite the popularity of apps like Daysy, obviously, this contraceptive method has serious flaws. The key to successfully avoiding pregnancy using the rhythm method is pinpointing the time of ovulation perfectly, which isn’t always easy — particularly considering the fact semen can remain viable for days after intercourse. 

Chicago-based doctor, Dr. Fred Nour, M.D. explained that the rhythm method dangerously assumes that a woman has a perfect 28-day cycle and that she ovulates on the 14th day of each cycle, which isn’t always the case. “This is not reliable at all as women do not ovulate on the same day of the cycle every month nor do they always have a 28-days cycle,” he told Sporteluxe.

There’s also some recent research that supports Dr. Nour’s sentiments: A study from Georgetown University Medical Center revealed that women using smartphone apps to monitor their fertility levels are at a higher risk of unwanted pregnancy.

So while fertility trackers are a great way to get in-tune with your body and prepare for PMS, you might want to pause before handing over control of your contraception to an iPhone.