Natural Cycles is the first smartphone application (“app”) for contraception cleared by the FDA. It is a high-tech version of the classic rhythm method (also called natural family planning or the fertility awareness method) in which users track their ovulation cycles in order to avoid pregnancy.
It is one of several dozen fertility apps available for download in the US that uses personal health information uploaded by users to predict days on which it is and isn’t safe to have unprotected sex. It is marketed as a new, technology-based, and “100% natural” form of contraception. Natural Cycles does not prevent against sexually transmitted infections.
Natural Cycles combines data about your menstrual cycle and your daily basal body temperature to predict when you’re most likely to get pregnant. Your basal body temperature (BBT) is your baseline temperature when you’re completely at rest. You can learn more about BBT and how it is measured here.
Natural Cycles is not a “standalone” contraceptive method. Natural Cycles is most effective for people who have not been on hormonal birth control within 12 months prior to using the app. If you have used hormonal contraception—such as the pill, patch, ring, shot, implant, or hormonal IUD—within 60 days of starting Natural Cycles, you are at increased risk of unintended pregnancy.
If you have an irregular menstrual cycle for any reason—for example, polycystic ovarian syndrome (PCOS)—or have recently been pregnant or had endometriosis, Natural Cycles is not recommended for you.
While the National Women’s Health Network strongly endorses the kind of body knowledge and self-care which Natural Cycles and other fertility awareness apps can foster, we have strong concerns about the app’s ability to replace other forms of contraception for most people.