Measure your temperature first thing in the morning, enter it into the app and know when you need to use protection or abstain from sex to prevent a pregnancy.
Before ovulation happens in the menstrual cycle, there is a detectable rise in basal body temperature caused by hormones. Basal body temperature, or BBT, is the body’s lowest resting temperature which you can measure first thing in the morning when you wake up. To measure this small, but significant, rise in BBT you need a thermometer which shows 2 decimal places.
The Natural Cycles app uses an algorithm which analyzes basal body temperature to tell you when you can get pregnant. To use Natural Cycles you need to add it to your morning routine. Measure in your mouth as soon as you wake up. You should aim to do this 5 days a week. Add your temperature data into the app, you can also input additional info like period data, LH test results and sex to get more out of the birth control app. It’s not essential to share this, but it can help the algorithm get to know your unique cycle.
After measuring, you should check your fertility status for the day. This is shown in the app as a green or a red day. A green day means you are not fertile and can’t get pregnant, a red day means you are fertile and there is a risk of pregnancy. On red days you should either use a condom or abstain from having sex. You can also see a forecast of your fertility in the calendar view, this only gives predictions and you should always check your daily fertility status. Natural Cycles does not protect against STIs.