3 reasons I wouldn't use a contraceptive app

After months of cystitis and thrush, I gave up the contraceptive pill for good...

I was about 19 at the time and I’d heard from a friend that it might be the cause, and they were right. So I started using my first ever hormone-free contraceptive (aside from condoms): the fertility awareness method (FAM).

Unless you’ve been trying to get pregnant you probably won’t have heard of it. It takes information like your waking temperature, cervical mucous and cervix position into account to tell when you are ovulating and therefore should avoid sex. But it’s having a revival with the invention of fertility tracking apps. One of these apps has gone so far as to become registered as a contraceptive called Natural Cycles (1). The only trouble is, I’m not so sure it can be trusted…

I love a good app as much as the next millennial but I’ve been practicing fertility awareness for a lot longer than the apps have existed and I have my concerns. 

While the app is 93% effective, the pen and paper method I learnt is up to 99% effective (2)! I’ve tried these apps and have yet to find one which can tell me when I’m ovulating more accurately than I can for myself. But I know that the apps learn your cycle the more you use them. So I need to try the Natural Cycles app for a few months to get an accurate picture. 

1. It says it works after less than a month of charting

Nevertheless, Natural Cycles says it begins to work after just 2 weeks of use (3). Which doesn’t make sense to me at all. FAM shouldn’t be relied on for contraception for at least 3 months (4). Till you have a handle on it. The same must surely be true of the app as it learns your cycles. Although learning FAM can seem daunting, once you know your body well enough you can do away with the charts. I haven’t kept a chart for years. I just know when I’m ovulating through my cervical mucous and how I’m feeling. I’ve even checked this accuracy using ovulation tests! 

2. It’s missing 2 fundamental pieces of info

But it did take me a few years to get to that point. What I don’t like about the app is that it doesn’t actually teach you FAM, it just takes your waking temperature and average cycle length to dictate 10 days in which you shouldn’t have sex, making you reliant on the algorithm. Whereas, FAM teaches you how to interpret the signs and symptoms of your body till you don’t need a chart. The app omits cervical mucous and cervix position. Which reduces its effectiveness (4). 

It only uses your waking temperature. Taking your waking temperature can only ever tell you after you’ve ovulated because your temp needs to rise by 0.2 degrees for 3 consecutive mornings. Natural cycles is being quite cautious by allowing 10 days for the fertile window when there is only a 5% chance sperm will survive more than 4.4 days and a 1% chance sperm will live more than 6.8 days in a fertile woman (5). Which makes the 93% effectiveness worrying as it implies those 10 days aren’t as accurate as the apps website makes out. 

Recently the app was reported to authorities in Stockholm after 37 women seeking abortions were discovered to have been users of the app (7). But maybe they fit inside the 7% of ‘error’ that their research predicts even with perfect use. We can’t know unless someone tells us how many women were using it who didn’t get pregnant in correlation with those 37 which did. 

3. The research was done by the company themselves

However, the research on its effectiveness was done by the app creators themselves (1). I’m not sure who else would invest in that though. It’s the same with most drugs. Research is expensive and only worthwhile if the research can be used to make money in the end. So I’ll remain skeptical till an independent study is done. After all, drug companies who conduct their own research aren’t exactly known for their impartial results. 


I’d like a free membership so I can test them over a longer time scale for one *hint*. I also want them to tell me exactly how they work. But that will never happen as it would reveal their trade secrets. Failing all that, some impartial evidence would be great. As women become more disillusioned with hormonal contraceptives we need to raise awareness of non-hormonal options. Which is why I really want these apps to work. But until they incorporate cervix position and cervical mucous I won’t be recommending them.

For more information about non-hormonal contraceptives see my blog about condoms, and the IUD



1. Scherwitzly, E. et.al. (2016) Fertility awareness-based mobile application for contraception. The European Journal of Contraception and Reproductive Health Care. 21, (3), p.234-241

2. NHS, (2017) Natural Family Planning. NHS. [online] Accessed 15/1/18: https://www.nhs.uk/conditions/contraception/natural-family-planning/?

3. Natural Cycles (2017) How it Works. [online] Accessed 14/1/18 from: https://www.naturalcycles.com/en/contraception/howitworks

4. Knight, J. (2016) The Complete guide to Fertility Awareness. Routledge: London.

5. Ferreira-Poblete, A. (1997) The probability of conception on different days of the cycle with respect to ovulation: An overview. Advances in Contraception. 12, (2-3), p.83-95. 

6. Davis, N. (2017) Can an app really provide effective birth control? The Guardian. [online] Accessed 12/1/18 from: https://www.theguardian.com/society/2017/oct/15/can-apps-provide-effective-birth-control-contraception-sexual-freedom

7. Murphy, M. (2018) Natural Cycles contraceptive app reported after influx of unwanted pregnancies. The Telegraph. [online] Access 8/3/18 from: https://www.telegraph.co.uk/technology/2018/01/16/natural-cycles-contraceptive-app-reported-influx-unwanted-pregnancies/