The UK's only certified contraceptive app

Yes. The effectiveness of Natural Cycles is supported by clinical evidence, which shows Natural Cycles is 93% effective under typical use. Under perfect use, i.e. if you never have unprotected intercourse on Red Days, Natural Cycles is 98% effective. Read more on the science behind our effectiveness.

Forgetting to measure doesn’t impact how effective NC° Birth Control is at preventing pregnancy. However, if the app doesn’t have enough data due to poor sleep or forgetting to measure, you might get more Red Days (when you’ll need to abstain from sex or use protection).

You don’t have to wait for Natural Cycles to learn your cycle before you can start using it because – Natural Cycles is effective from the first day of use!

We are FDA Cleared in the US and CE Marked in Europe as a medical device for contraceptive use. We are also listed in the ARTG in Australia and on the SMDR in Singapore. We have received a Class II Medical Device License from Health Canada to be used as birth control. Our certifications have been granted based on mandatory clinical data that demonstrates that the effectiveness rate of Natural Cycles is 93% with typical use and 98% with perfect use (when using protection on each Red Day). Natural Cycles is the first app to be assessed and recognized as a method of birth control in Europe and the US. Read more about our regulatory clearances.

Natural Cycles is the first and only app of its kind to be FDA Cleared and CE Marked. Most other fertility apps assume your cycle is 28 days long. This means the fertile window they give you is not personalized to you. Our algorithm significantly reduces the risk of you being assigned an incorrect Green Day as it uses your personal data. This reduces the risk of unwanted pregnancy or can help you plan pregnancy with greater precision. 

Find out why women around the world choose Natural Cycles.

Women should never have to rely on uncertified period-tracking apps as a form of birth control. Our goal is to provide women in the UK who are using unregulated methods with immediate access to an effective, certified contraceptive method. If this applies to you, then you're eligible to access Natural Cycles at no cost for the next three months to determine if it's the right option for you. If you’re already using a prescribed birth control method, speak to your doctor before switching to Natural Cycles.

Analyzing your unique temperature data is key to how Natural Cycles works, but as we know everyone’s routine is different. Temperature data can be collected using the NC° Thermometer (this is different to a regular fever thermometer), or by pairing a measuring device like an Oura Ring or a compatible Apple Watch with the Natural Cycles app.

With the NC° Thermometer, measure your temperature (first thing) when waking up (before sitting up, drinking water, snoozing, or getting out of bed). We recommend keeping the thermometer close to your bed. After measuring, open the Natural Cycles app to sync your data and see your daily fertility status.

With an Oura Ring, your temperature trend data is measured overnight. Wear your Oura Ring to sleep. When you wake up, open the Oura App and NC° app to sync your data and see your daily fertility status. If you are using a Gen3 Oura Ring or later, you will also need an Oura subscription to use the integration.

With Apple Watch, your temperatures are measured and sync with the Natural Cycles app while you sleep. Wear your Apple Watch Series 8+ to bed at night. Open the NC° app to see your daily fertility status when you wake up. 

Discover which device is right for you.