Welcome to 
Natural Cycles

The digital fertility awareness-based method that predicts daily fertility to either prevent or plan pregnancy. 93% effective with typical use, 98% effective with perfect use.


Available In

A certified medical device

The first and only birth control app to be FDA cleared 
in the US and CE marked in Europe (device classes II/IIb).

What is Natural Cycles?

Natural Cycles is a fertility awareness-based method composed of an app and a thermometer. The app is powered by an algorithm that adapts to each woman’s cycle, using temperature data to determine fertile days. Unlike calendar-based trackers, this provides a personalized fertility status for each user.

Access to a daily fertility status means a woman can prevent pregnancy by abstaining from sex or using protection on her fertile days. Natural Cycles can also be used in ‘plan mode’ to help women conceive when they want to start a family.

How does it work?

The algorithm uses basal body temperature, menstruation data and optional LH test results to determine the fertile window. It confirms ovulation by analyzing temperature shifts caused by hormones.

The user takes her temperature most mornings when she wakes up and enters the reading into the app. The algorithm then learns the pattern of her cycle and is able to assign a daily fertility status. This is given as either a red (fertile) day or a green (non-fertile) day. 

Unlike other fertility awareness-based methods, Natural Cycles adapts to each woman’s cycle, predicting and confirming her specific ovulation. This means Natural Cycles can be used by women with irregular cycles or conditions, such as PCOS, helping them gather data to present when discussing potential health concerns.

How effective is Natural Cycles?

Natural Cycles is 93% effective with typical use and 98% with perfect use. Our FDA clearance is based on a study of over 15,000 women, while our certification in Europe is based on 22,000 women. Natural Cycles is the only app regulated for contraceptive use.

Typical use effectiveness includes users who have unprotected sex on fertile days, whereas perfect use counts only users who abstain or use protection on fertile days.

93% typical use effectiveness is based on a 100 women using the method over 12 months, meaning on average 7 women out of the hundred get pregnant using Natural Cycles in a year.

Compare Natural Cycles with 
other contraceptive options

Here you can see how our effectiveness lines up 
with common hormonal & non-hormonal methods.

Birth Control Method
Phone with the natural cycles app and thermometer
Natural Cycles
Two contraceptive pill strips
illustration of a male condom
Male Condom
hormonal iud illustration
Hormonal IUD
Illustration of NuvaRing
illustration of a calendar with some days crossed out
Ovulation Method (Calendar Rythm)
hand with crossed fingers
Pull Out Method
*Typical use %
*Perfect use %

*Percentage of typical/perfect users who did not get pregnant with the method over 1 year of use.

Reference: Contraceptive Technology (Table 26 - 1). 21st Edition, 2018 —>
Source: Trussell J . Contraceptive Efficacy. In Hatcher R A, Trussell J, Nelson A L , Cates W, Kowal D, Policar M. Contraceptive Technology: New York NY: Ardent Media, 2018—>

Talking to your patients 
about Natural Cycles

Why not get in touch?

We’re always interested in talking with healthcare professionals and working with businesses in the field of women’s health. If you’re curious about collaboration, or simply want to know more about what we’re doing, why not reach out to our team?

Dr. Jack Pearson (PhD)

Medical Affairs Manager

Add your details here 
and we’ll get in contact.