Birth Control Apps

Birth control? There’s an app for that! Not a good one, but the slick marketing campaign associated with the Natural Cycles app has persuaded hundreds of thousands of women worldwide to put their contraceptive trust entirely in the hands of an app.

In 2017, an app called Natural Cycles was approved across the EU and in 2018 approved by the FDA as a Contraceptive Method. The FDA reviewed the Natural Cycles app through a regulatory pathway for novel, low-to-moderate-risk devices of a new type. This pathway requires much lower standards for proof than the regular approval pathway for medications. I find it distressing given the current US climate around criminalizing abortion, that the low risk of the DEVICE was considered and the high risk of an unwanted pregnancy was not.

It is not approved for contraception in Canada, however, the app is available on the Canadian app store and they are happy to bill you $99.99 in Canadian dollars for a yearly pregnancy prevention subscription. For your $100 you get an app and a thermometer sent to you by mail.

The Natural Cycles app is a step back in terms of accuracy compared to the old-fashioned Rhythm method. Over the generations, the Rhythm Method has evolved to improve predictability. Symptothermal methods of Fertility Based Awareness Methods (FBAM) track the effects of estrogen (cervical mucus) together with the effects of progesterone (basal body temperature) and plot that on a calendar of your previous cycles.

With new technology, we got an even more direct way to measure fertility in FBAM. The Marquette Method uses Clearblue fertility monitors to measure estrogen and LH levels directly. LH is the hormone responsible for ovulation; it occurs about 36 hours before that egg pops. Testing once daily though, can identify the LH surge late, and even with on-time identification sperm can fertilize an egg up to five days after ejaculation. The Marquette Method works better for planning a pregnancy than planning to avoid one. Marquette costs about $500 for the training and monitor, and about $20 per cycle in test strips.

So how does the Natural Cycles app compare to Symptothermal and Marquette methods of FABM? The app only requires one input: your temperature as soon as you wake up, and the app makes predictions about your fertility each day: green for “go have unprotected sex”, red for “not unless you want a baby”. It is actually less predictive than the old-fashioned Rhythm method.

The ideal user of this app has a very predictable life. They have a monogamous relationship, sleep soundly and wake at the same time every day in the same bed (no travel or shift work), their periods are precisely the same length every month, and they’re ready to have a baby even if it’s not the perfect time yet. Their partner is onboard with abstaining from sex most days for the first few months and about 6-9 days per month once a pattern is established.

In 2014 the New York Times published a really helpful set of graphs that can tell you the cumulative effect of using different contraception over your lifetime. Back in the old days you started having sex at 17 and got married at 19. You had to stay not pregnant for a year or so. Nowadays people want to stay not pregnant from 17 to 38! That requires a very different level of effectiveness! The NYT graphs show Fertility Awareness based methods resulting in 24 pregnancies in 100 people with typical use (because none of us are perfect) after 1 year, and 42 in 100 after 2 years. Real talk - FABM is not a great way to stay unpregnant. If you’re hoping to prevent a pregnancy for 10 years, you really need to consider a method with high efficacy, something we call a LARC (long acting reversible contraceptive) like IUD or Nexplanon.

https://www.nytimes.com/interactive/2014/09/14/sunday-review/unplanned-pregnancies.html

In order to receive FDA approval, Natural Cycles did their own studies which showed a pregnancy rate of 7% per year, however, the study design was not good. A better study, by the makers of a similar app called Dot, analyzed users lost to follow-up and determined that the actual pregnancy rate may be closer to 13% by the end of year 1.

The biggest problem with all Fertility Awareness-based methods is that they make a prediction about risk based on your pattern from previous months. But anyone who menstruates knows that once or twice a year your body will surprise you. Usually the only surprise is ruining a good pair of panties, but if you’re using FABM and your cycle just goes a little wrong one month, the surprise will be a pregnancy.

It’s also super important to know that the Emergency Contraception pill (Plan B) works by delaying ovulation by a day or two. So if you’ve used Plan B, your cycle monitoring will be thrown off for a couple of months until it recalibrates.

The company states that the Natural Cycles app is not for anyone who would be devastated by a pregnancy. I often ask patients “would it be the end of the world if you got pregnant?” If the answer to that is yes, this is not a good contraceptive plan for you.