Apps such as NaturalCycles® are being used by many women around the world as a natural, non-medical method of contraception. These apps are medical devices, which in principle have to meet the same requirements of effectiveness and safety as drugs. These should preferably be established by randomised studies. The NaturalCycles®-app might appear to be suitable for a selected group of highly motivated women to determine moments during a menstrual cycle when there is no risk of pregnancy. This does, however, require daily input of accurate data, like body temperature. There is no evidence from randomised studies that such an app is just as effective or ineffective as oral contraception, not even with flawless use. As long as this evidence is not available, care providers should not recommend this type of app as a contraceptive method.
- Care providers need to be aware of the major limitations of using an app as a means of contraception.
- The reliability of NaturalCycles® (a contraceptive app) is based on an algorithm to predict, with unknown uncertainty margin, the days on which a woman is not at risk of becoming pregnant.
- Diagnostic apps predicting when a woman cannot become pregnant are not testable, as there is no gold standard reference test to determine ovulation.
- Variations in menstrual cycles, uncertainty about the exact moment of ovulation, the importance of disciplined and accurate data input, and the need for supplemental contraception limit the general applicability of contraceptive apps.
- No randomised studies into the effectiveness of contraceptive apps are known in which the pregnancy risk was directly compared with the risk when using hormonal contraception.
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The literature refers to the Dutch text