Grounded in Science: Dedicated to Research

Discover the data behind the first and only contraceptive app. Our mission is to pioneer women’s health with research and passion, read on to find out how we make it happen.

What does research look like at Natural Cycles?

Natural Cycles is 93% effective with typical use and 98% effective with perfect use. Our effectiveness comes from an analysis of over 15,000 women. The study looked at all possible reasons women become pregnant when using Natural Cycles. This includes having unprotected sex on a red day, to the app wrongly giving a green day, to a condom breaking.

Our Newest Study is Here:

In collaboration with UCL, Natural Cycles studied over 600,000 menstrual cycles of more than 124,000 women. Menstrual cycles are very varied with only around one in eight women having a 28-day cycle. Read more on the study….

Did you know that we have a dedicated team committed to research? We regularly contribute with scientific involvement in the historically overlooked area of fertility and women’s health. Check out our published studies on Natural Cycles below:

  1. E. BERGLUND SCHERWITZL et. al., Perfect-use and typical-use Pearl Index of a contraceptive mobile app, Contraception, Volume 96, Issue 6, 2017, p. 420-425 →
  2. E. BERGLUND SCHERWITZL et. al., Fertility awareness-based mobile application for contraception, The European Journal of Contraception and Reproductive Care, 2016, p. 234-241 →
  3. E. BERGLUND SCHERWITZL et al. Short- and long-term effect of contraceptive methods on fecundity, The European Journal of Contraception and Reproductive Care, 2019, p.1-6 →
  4. Jonathan R. BullSimon P. RowlandElina Berglund ScherwitzlRaoul ScherwitzlKristina Gemzell Danielsson, Joyce Harper.Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles. Nature, 2019.

What is perfect use?

  • 98% effective means that 2 women out of 100 will get pregnant during 1 year of use, even with using the app perfectly
  • Perfect use is when you do not have unprotected sex on red days, i.e. always use a condom or abstain from sex
  • To be a perfect user, you do not need to measure every day at the same time, but you do need to use protection on every red day
  • Perfect use also includes women who had unprotected sex on a green day that was falsely given, or had protected sex on a red day but the method failed (e.g. a broken condom)

What is typical use?

  • Typical use shows how many women on average get pregnant due to all possible reasons
  • The most common reason for pregnancy with Natural Cycles is the failure to use protection on red days
  • Typical use includes pregnancies that occurred under perfect use
  • 93% effective under typical use means that 7 out of 100 women will get pregnant during one year of use

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