Smartphone Contraception


Can an app replace your patients’ birth control?

Response from Zara Risoldi Cochrane, PharmD, MS (January 08, 2019)[] Associate Professor of Pharmacy Practice, Creighton University School of Pharmacy and Health Professions; Director, Center for Drug Information & Evidence-Based Practice, Omaha, Nebraska

A mobile app designed to prevent pregnancy made headlines earlier this year when it became the first medical application cleared by the US Food and Drug Administration (FDA) for the purposes of birth control.

The science behind the app isn’t new—fertility awareness-based methods of contraception have been used and studied for decades—but questions remain about the Natural Cycles app, and whether a software program can truly replace your patients’ birth control.

The App

The Natural Cycles app uses a fertility awareness method based on basal body temperature (BBT). Women enter their temperature into the app each morning, as well as information regarding their menstrual period. Using a proprietary algorithm, Natural Cycles analyzes BBT trends to accurately predict a woman’s daily fertility.

The results are depicted using a simple color-coded graphic. A green circle indicates that the user is not fertile and can have intercourse without the need for additional protection against pregnancy. A red circle indicates a fertile day and alerts the user to use protection (such as a condom) or abstain from intercourse. Natural Cycles learns a woman’s cycle as more and more information is entered into the app, making its predictions more accurate with continued use.

In addition to BBT and menstruation, users can choose to track their luteinizing hormone levels (this requires a separate urine test strip). In predicting fertility, the app’s algorithm accounts for temperature fluctuations; sperm survival; ovulation day; and variations in menstrual cycle length, including the follicular and luteal phase. What makes Natural Cycle unique from other fertility awareness-based methods is that it digitizes and automates this analysis, eliminating the need for patients to manually chart and interpret their data.

Natural Cycles requires an Internet connection and is compatible with Android and iOS smartphones, as well as other devices with a Web browser. The cost of the app is $9.99 per month or $79.99 for an annual subscription. A free 1-month trial is offered for new users.

Is It Effective Birth Control?

Natural Cycles is promoted as being 93% effective at preventing pregnancy. According to the FDA, the app has a “typical use” failure rate of 6.5% and an “ideal use” failure rate of 1.8%. This puts it roughly on par with injectable contraceptives (typical use failure rate, 6%) and more effective than oral contraceptives (9%).

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