Natural Cycles and other contraceptive options


The information and questions provided below are designed to support your counseling so that you and your patients can make informed choices.

Who is Natural Cycles suitable for?

Natural Cycles may be suitable for women who are looking for a natural method of contraception and have a lifestyle that enables them to take their temperature first thing most mornings.

  • Women using Natural Cycles should be at least 18 years old (users of Natural Cycles are 30 years old on average)
  • To use Natural Cycles, women must be willing to use protection or abstain from sex on red days
  • Natural Cycles may be suitable for women who are interested in learning about their cycle and have a desire to be more in tune with their body
  • Natural Cycles is also a suitable option for women who are considering a pregnancy

Evidence shows that a woman who, following consultation with her HCP, has actively chosen a method of contraception and is satisfied with it, is more likely to use it consistently and correctly. On the other hand, women using a method which is not in line with their personal preferences may be less likely to adhere to, or continue with that method, which could increase the risk of an unplanned pregnancy.¹This is why contraceptive choice is so important.

Who is Natural Cycles less suitable for?

  • Natural Cycles is less suitable for women with irregular menstrual cycles (i.e. cycles with length less than 21 days or greater than 35 days), since predicting her fertile days is more difficult and as such, the number of red days will be higher.
  • Natural Cycles is less suitable for women who have a medical condition where pregnancy would be associated with a significant risk to the mother or the fetus.

Instructional Video for Healthcare Professionals

Aspects to consider before recommending Natural Cycles

More red days in the beginning

The algorithm adapts to every woman’s unique cycle pattern by learning over time as she adds more data. The number of green days increases accordingly, therefore, a woman who inputs temperature readings regularly and often (at least 5 times a week), has a regular cycle and a non-deviating temperature is likely to receive more green days. The algorithm has been intricately designed to account for sperm survival, variation in cycle length, ovulation day, temperature fluctuations and the length of the follicular and luteal phase, and is sensitive to subtle patterns in a woman’s cycle.

In light of this information, it is necessary to inform patients that patience is required over the first few weeks, and that it may take several cycles of consistent measuring and entering data for the app to become familiar with a woman’s individual cycle and detect ovulation. As such, it is normal that more red days are given initially.

  • Having recently stopped hormonal contraception
  • Highly irregular cycles
  • Atypical fluctuating temperatures

Women discontinuing hormonal contraception

For women who have recently stopped using hormonal contraception, it is not unusual to experience anovulatory cycles for a couple of months.

A woman can start using Natural Cycles the day after she discontinues using hormonal contraception. Until her first ovulation is detected, she should expect many red days as a Prevent user.

IMPORTANT: women should not measure while still on hormonal contraception since the hormones inhibit ovulation and also affect temperature and cycles. Therefore a combination of hormonal contraception and Natural Cycles is not possible.

Women with irregular cycles

Small irregularities are quite common, especially if a woman has recently stopped using hormonal contraception. The Natural Cycles algorithm takes factors such as cycle regularity and temperature fluctuations into account when analysing individual cycles and calculating fertility status for the day.

Natural Cycles may be less suitable as a contraceptive if a woman’s cycle is very irregular, since she will get more red days, yet by tracking her cycle, she will get to know how her own individual cycle.

1Berglund Scherwitzl E, Lindén Hirschberg A, Scherwitzl R. Identification and prediction of the fertile window using NaturalCycles. The European Journal of Contraception & Reproductive Health Care. 2015;20(5):403-408.
Contraceptive Method% of women experiencing
an unintended pregnancy
within the first year of use
Protection against
User-dependentPotential non-
Potential side effects
Natural Cycles¹7NoYesYes⁴No
Copper IUD²0.8NoNoNoYes⁵
Hormonal IUS²0.2NoNoYesYes, hormone-related
Traditional³ fertility
Male condom²18YesYesNoNo
Combined pill and
progestin-only pill²
9NoYesYesYes, hormone-related

¹Berglund Scherwitzl E, Lundberg O, Kopp Kallner H, Gemzell Danielsson K, Trussell J, Scherwitzl R. Perfect-use and typical-use Pearl Index of a contraceptive mobile app. Contraception. 2017;96(6):420-425.
²Trussell J. Contraceptive failure in the United States. Contraception. 2011;83(5):397-404
³Non-digital, without the help of a personalised algorithm
4Hatcher R. Contraceptive technology. 20th ed. [New York, N.Y.]: Ardent Media; 2011.
5E.g. Cramps, pelvic infections, heavier periods, ectopic pregnancies

Natural Cycles’ effectiveness is based on clinical research, please see the results of our peer-reviewed publications.


Downloadable files

Patient Brochure