Natural Cycles has announced a partnership with Oura and it's one that could be a game changer for users of the FDA-cleared birth control app if they also use an Oura Ring.

The Natural Cycles app works by analysing hormone-driven temperature patterns, along with other key fertility indicators, to determine whether a woman is fertile or not in order to help plan or prevent preganancy.

Users get red days (fertile) or green days (not fertile) if they have chosen the prevent pregnancy mode, and vice versa if they have selected the plan pregnancy mode. In order for the algorithm to work out these days for each user though, you need to enter your temperature into the app as many days as possible in the month, which you need to take using an oral thermometer when you first wake up. You also have to take into account different sleep patterns or alcohol, and giving the app the correct information.

The partnership with Oura - the company responsible for the Oura Ring, a smart ring that delivers personalised health data, insights and daily guidance makes that process much more streamlined. Rather than having to manually take their temperature, users with an Oura Ring that switch to the Oura Mode in the Natural Cycles app will have this done automatically. 

According to Natural Cycles: "The temperature sensors in the Oura Ring generate 1,440 data points each day, and are validated to measure temperature changes as precisely as 0.13°C (0.234°F).

"In addition to temperature trend data, the Natural Cycles algorithm uses heart rate data from the Oura Ring to take into account nights with elevated heart rates that may be due to lifestyle changes, such as high alcohol consumption, rather than due to menstrual cycle changes."

The Oura Ring also tracks and analyses sleep quality and it has features like Daytime Heart Rate, Workout Heart Rate, and Automatic Activity Detection to evaluate movement and restorative time. These personalised health metrics are then summarised into Sleep, Activity, and Readiness Scores. 

While the benefits only come to those who use both the Natural Cycles app and have an Oura Ring, it's big news for those wanting to use a hormone-free method of contraception and not have the chore of entering temperature data each morning for the best results.