Natural contraception: does it actually work?

Now I’ll be honest, I know nothing about clothing fashion, but I know a thing or two about contraceptive fashion. And it’s fair to say, in central London at least, the contraceptive pill really seems to have had its day. This is of course my anecdotal evidence only, but lots of people say it’s because they want to consider hormone-free options. There are several hormone-free methods of contraception out there including the copper coil and the good old condom, but it’s natural family planning methods that is getting a lot of social media attention. There is also a particular app, called Natural Cycles that has a lot of bloggers and influencers singing its praises. But is natural family planning actually any good?


Natural family planning, also known as the fertility awareness method (FAM) is not a new concept at all and it’s been around for centuries. The aim of the game is to understand your menstrual cycle to begin to predict the fertile period, and avoid having sex at that time. You’ll probably remember from biology classes at school that the menstrual cycle is 28 days long according to text books. That means of day one is the first day of your period, your next period will start exactly 28 days after that. In this scenario, ovulation should occur on day 14, and when the egg is released it can survive for up to 24 hours and if its isn’t fertilised it dies. However, the fertile period technically begins 5 days prior to ovulation, because sperm can survive for up to 5 days in the human body, and therefore this fertile window is actually 6 days long, from day 9 to day 15 with a 28 day cycle, and if you want to avoid pregnancy you would need to either abstain from sex, or use condoms during these 6 days. Using this method alone, about 25% of women will get pregnant in a year. Errrrrrm…One. In. Four. As you can see, the odds of getting pregnant are about the same as the bookies favourite winning the Grand National.


So what about Natural Cycles? It’s the only ‘certified contraceptive app’ and if influencers with tens of thousands of followers are saying it’s the way forward it must be legit right? Well, in my opinion, it’s not wrong but there are some caveats that I want you all to be aware of.

When you subscribe to the app, you are supplied with a thermometer. By taking your temperature every day and putting this into the app along with the dates of your last periods this improves the accuracy of predicting ovulation, based on the rise in basal body temperature of around 0.3°C that happens at the time of ovulation. Based on this information the app with give you a result for that day; either green (safe to have sex) or red (don’t have sex, or use a condom). For the average user, with an average 28 day cycle, the manufacturers state that you should eventually get about 10 red days, because the app uses a very conservative estimation in order to improve the effectiveness at preventing pregnancy, which with typical use is 7.5% in a study of 4054 women. It’s important to note here that the typical use pregnancy rate for the pill is 9% and condoms are 15%. So if Natural cycles is numerically better, why do you get the feeling I’m about to tell you proceed with caution? Firstly, if you actually take the pill properly the failure rate is only about 0.5%, and if you put a condom on before you have any genital-genital contact and it doesn’t slip off or break the failure rate is about 2%, and this is called perfect use. The studies on natural cycles state with perfect use the failure rate is also 0.5% like the pill, but that’s only based on estimates of how often the app would wrongly attribute a red day as a green day. But you have to remember, we are humans, and not mathematical algorithms. So why would the app get it wrong? Many reasons. These include; not taking your temperature at the same time every day, having a temperature due to illness, being on a different time zone that affects your circadian rhythm, or you just happen to ovulate on a day the app didn’t predict. And the latter may be surprisingly common. There are plenty of reasons why ovulation doesn’t occur on the predicted day, and that may be because you’re stressed, you overtrained, you have a poor diet, you had a disrupted sleep cycle, you were jetlagged….the list is endless. Or maybe you have an irregular cycle, which isn’t a contraindication to using these types of fertility awareness methods, but it means that natural cycles for example would give you a LOT of red days. So that’s lots of days when you’re keeping those legs closed, or popping out to stash up on rubber johnnie’s (do the kids even call them that these days?). Basically if you ovulate earlier than expected and you’ve had unprotected sex within 5 days you are at risk of pregnancy because the rise in temperature only happens on the actual day of ovulation so the app won’t be able to protect you.


So in summary, the app will work as contraception if it correctly calculates the day that you ovulate, and you either use a condom, or don’t have sex on the red days. I also truly believe that it’s only really suitable as a contraceptive for women who would not be devastated if they did get pregnant. I certainly don’t criticise anyone who does want to use these apps as their contraception, but I do believe in helping people making informed decisions. Personally for me it would not be reliable because I work nights, am frequently stressed and have terrible sleep hygiene.


One thing I do really think Natural Cycles is great for is helping you to get to know your menstrual cycle, which can be really empowering for women and also really helpful if you’re thinking of trying to get pregnant in the near, or medium-term future. Plus if you’re actively trying to get pregnant, you can use the app the opposite way round and use it to help you work out when you’re fertile, so that you can arrange plenty of date nights during the red times (*insert winking emoji).


On a final note, there are other contraceptive apps out there (although most are far less effective, and an interesting study showed exactly how ineffective they can be), but Natural Cycles is the one I’ve seen people talking about most on social media, which is the reason I chose to talk about it, mainly to reinforce my final message is that you have to be careful who you trust on social media. Always check people know what they’re talking about and remember just because it works for one person doesn’t mean it’s the best option for you. Bad fashion advice is easier and less heart-breaking to rectify than an unwanted pregnancy.