Does Natural Cycles Really Work? |
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Would you rely on an app to prevent unwanted pregnancy? With the number of UK women using the Natural Cycles App as a form of contraception soaring from 5,000 last year to more than 125,000 this year, the statistics would suggest so. But despite being the first app to be certified by the European Medicines Agency as a legitimate form of birth control, a new wave of allegations suggest it may not be effective as it claims. We did some delving...

What is Natural Cycles?

A £40-a-year app that monitors body temperature to give you an indication of days on which you can fall pregnant in your cycle (there are only six per cycle according to the app’s makers).  The app requires users to take their temperature every morning as soon as they wake up, using a special thermometer that measures to at least two decimal points. Slight changes in temperature indicate hormone fluctuations that can predict ovulation, but these differences are so minute that a normal thermometer wouldn’t pick them up. After a few months of readings, Natural Cycles will get to know your cycle and map out ‘green’ days and ‘red’ days (users report there are more red days in the initial few weeks as a precaution). Green means risk of pregnancy after unprotected sex is low and red that risk is high, meaning users should consider either abstaining or using protection.

Why use it?

The premise might seem simple and you might wonder why you need an app at all, but many women have irregular cycles, which makes it more difficult to predict ovulation. To further complicate the matter, sperm can live in the body for up to 72 hours, so if you were to have sex a day or two before ovulation, you could still fall pregnant. The app therefore works by predicting your fertility window, which extends a few days on either side of ovulation. The app claims to be 93% effective in preventing unwanted pregnancies (in comparison, the contraceptive pill is 91% effective) while being hormone and thus side effect-free.

So it’s a reliable form of contraception?

Yes, but only when used correctly. And while Natural Cycles may be the only certified birth control app in Europe, it’s still seeking approval to be used as an official method of contraception in GP surgeries and sexual health clinics in the UK, and large independent trials are yet to be carried out. Moreover, while the NHS claims methods such as tracking body temperature can be up to 99% effective in preventing unwanted pregnancies, experts have added that when typically used (i.e. taking into account human error), it’s more likely to be around 76% effective. Studies also claim your temperature can be affected by being ill, hungover or sleep deprived. A separate study also found that for every 100 women who used the app in a ‘typical’ way each year, seven fell pregnant.

What’s the latest?

Birth control app Natural Cycles, which uses tech-enabled fertility tracking to help prevent unwanted pregnancies, is under fire for reportedly leading to 37 unwanted pregnancies in Sweden. A hospital in the capital of Stockholm reported the app to the country’s medical regulator after nearly 40 women visited the hospital for an abortion in the last four months of 2017, having used the app as a contraceptive.

What’s been said?

A spokesperson from Natural Cycles has commented, “At first sight, the numbers mentioned in the media are not surprising given the popularity of the app and in line with our efficacy rates. As our user base increases, so will the amount of unintended pregnancies coming from Natural Cycle app users, which is an inevitable reality.” The app currently has around 700,000 users worldwide.

The bottom line?

If you’re looking for a hormone-free birth control alternative and are prepared to use it properly – i.e. recording temperatures daily and using contraception on red days – it could be for you. However, health experts say that if you suffer from irregular periods, have multiple sexual partners or have a partner who isn’t as committed to contraception as you are, these factors could weigh against you.
For more information on Natural Cycles, visit

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