Our Research & Birth Control Studies

We invest heavily in scientific research to further our understanding of Natural Cycles and the role it can play as a birth control method, pregnancy planner and in women’s health more generally. Because progress starts with research.

Perfect-use and typical-use Pearl Index of a contraceptive mobile app paper cover

Family Planning Studies & Typical Use

Results from a prospective study show that the typical use effectiveness rate of Natural Cycles is 93%. When Natural Cycles was evaluated as a software application for birth control contraception, an additional data analysis was performed. In this retrospective analysis of more than 15,000 women with a total exposure time of 7,353 women years, Natural Cycles demonstrated a typical use Pearl Index of 6.5. This means that in total 6.5 women out of 100 women get pregnant during one year of use.

When calculating typical use effectiveness in the study, all possible reasons for becoming pregnant while using the app were taken into account: from having unprotected sex on a red day to the app wrongly attributing a green day or the chosen method of birth control on a red day having failed.

It is important to note that the effectiveness of Natural Cycles relies on using protection (e.g condoms) or abstaining from sex on red days. If temperature readings are irregular or inconsistent, the algorithm will give you more red days.

Results from this study have been published in the renowned scientific journal, Contraception, and is available to view via the link below.

Learn more

Additional studies on Natural Cycles

In one of the largest ever prospective studies on natural birth control, a two-year analysis was designed to help us understand how effective Natural Cycles is as a method of birth control, and included over 22,000 women.

Further studies include the “Identification and prediction of the fertile window using Natural Cycles” which has shown that the Natural Cycles algorithm can accurately identify ovulation.

The study “Fertility awareness-based mobile application for birth control” was the first study ever performed on a mobile application used for birth control – and calculated the Natural Cycles typical use effectiveness rate for the first time. Based on results from this study, we went on to conduct the largest ever study into natural birth control, described above.

It is important to note that the typical use effectiveness rate with Natural Cycles has remained consistent since this very first study.

Both of these studies have been published in The European Journal of Contraception and Reproductive Care. Read more via the link below.

Learn more

How do I ensure Natural Cycles is effective for me?

Before you get started, read the User Manual thoroughly as this contains all the information you will need to use Natural Cycles effectively.

The most important thing to remember is that the effectiveness of Natural Cycles relies on you and your partner using protection (e.g. condoms) or abstaining from sex on red days.

You should also ensure that you are measuring correctly by using a certified two decimal basal thermometer underneath your tongue, just after you wake up and before getting out of bed.

Remember to read the User Manual carefully to make sure you understand any factors that could affect your basal (resting) body temperature – such as sickness, taking painkillers, long-distance traveling or feeling hungover. On these days, you should tap ‘Deviating temperature’ when adding your reading into the app.

The aim is to measure at least five days per week – the more frequently you measure, the more likely you are to get a higher number of green days.

Ready to get started? Get the annual subscription today, thermometer included.