Discussions about, and prescriptions for, contraception are one of the most common reasons women visit their doctors. From preconception counseling to prescribing oral contraceptives to intrauterine device (IUD) insertion to consults for sterility procedures, not a day goes by in my practice that I don’t perform one of the above interventions for my patients. Patients frequently depend on their providers to tell them about the pros/cons of various forms of contraception and help them troubleshoot any issues that come up along the way. For providers, we typically recommend resources such as the excellent pocketbook called Managing Contraception (not available as an app) and the CDC’s Contraception 2016. More recently, we favorably reviewed the outstanding app by Dr Joshua Steinberg and Dr Katherine Holmes from the Reproductive Health Access Project (RHAP) to create a quick reference app for students, residents and faculty in primary care called Contraception.

Sometimes patients ask about or require non-hormonal forms of contraception or are interested in knowing when they are ovulating to aid in conception. Basal body temperature monitoring is an ancient form of birth control and part of a family of pregnancy prevention methods called fertility awareness-based (FAB) methods. According to the literature, approximately 1-3% of women use these methods, but evidence suggests more would use it if they new about it. On August 10, 2018 the FDA approved the first FAB app for contraception called Natural Cycles. The app was created by nuclear physicist Elina Berglund Scherwitzl, a Nobel Prize winner who discovered the Higgs boson particle! The app was first launched in Sweden in 2014 then in other European countries. To their credit, three studies have been published on the efficacy of the app. One 2017 study was a prospective observational study of 22,785 users who logged 18,500 patient-years of data and demonstrated a Pearl Index of 6.9 pregnancies per 100 woman-years, a 13 month typical-use pregnancy rate of 8.3%, and a 12-month discontinuation rate of 54%. The Natural Cycles app studies additionally claim a typical-use effectiveness of 93% and a perfect-use effectiveness of 99%. These data are better than what is typically seen with traditional basal body FABMs, but still not as effective as long-acting reversible contraceptives (LARCs). A recent 2018 systematic review of 53 studies evaluating the effectiveness of FABMs for contraception, found the evidence to be low to moderate quality and the effectiveness for basal body temperature monitoring to be 9.0-9.8% for first-year typical pregnancy rates. One hospital in Sweden reported over 37 patients sought medical care for an abortion after using the Natural Cycles app.


Evidence-based medicine

This app has gained a lot of media attention making one believe that the concept of basal body temperature monitoring is new. Of course it isn’t, but the app makes the process easier than ever before for those interested in trying it out. The evidence as a whole for this form of contraction is poor to moderate in quality with upwards of 9% pregnancy rates, but certainly not on par with hormonal methods especially LARCs. The evidence for the app is merely OK, as like many forms of contraception it depends greatly on patient compliance/perfect use.

Who would benefit from this App?

Women interested in a non-hormonal method of contraception, women interested in conceiving, providers who provide contraception and/or infertility services including students, residents, mid-levels, Family Medicine, and Ob/Gyn.

Disclaimer: The views expressed are those of the author(s) and do not reflect the official policy of the Department of the Army, the Department of Defense or the U.S. Government.

  • Price
    • $9.99/month
    • Beautiful interface, process of use to make basal body temperature monitoring “easy.
    • Excellent instructions on use with detailed help section, links to additional products, thermometer calibration built into app, etc
    • Available for Android
  • Dislikes
    • Does not describe the efficacy of basal body temperature monitoring in the app (only online)
    • Cost may be a concern for some
    • Evidence for the app itself should be easier to find via the app itself
  • Overall

    Time will tell if Natural Cycle is revolutionary in its ability to bring basal body temperature monitoring for contraception/conception to the masses, but it certainly has a good chance to succeed.The app carries FDA approval and a slick interface the most will love. Pricing may be an issue for some users as will the simple fact that efficacy of basal body monitoring for contraception will never be as good as say long acting reversible contraceptives (LARC) such as Nexplanon and Mirena. Failure rates of upwards of 9% will (and should) give some women pause.

  • Overall Score
  • User Interface

    Seemingly easy to use and follow interface, but some may still find the entire process a bit too complicated.

  • Multimedia Usage

    Contains instructional video, easy to follow charts/graphs, links for additional products, detailed instructions and help sections.

  • Price

    App is subscription based: $9.99 per month (one month free trial). Also need basal thermometer and optional ovulation kits, condoms, etc.

  • Real World Applicability

    Natural Cycles is likely to become a huge hit for its developers. The app is easy to use, but the evidence on which it is based (basal body temp monitoring) is of poor to moderate quality. However, the evidence of the app itself is still developing, but based on published data is slightly better than non-app based FABMs. For patients who can’t or won’t use a hormonal-based contraceptive, Natural Cycles may be exactly what they have been waiting for to use. The app is likely to be most accurate when used as directed (the biggest nail in the coffin of many forms of contraception). Finally, the app can also be used to help women conceive giving an entirely different population a reason to try it out.

  • Device Used For Review

    iPhone 8 running iOS 11.4

  • Available for DownloadAndroidiPhoneiPad