This week, the Stockholm developers of the world's first birth control app, Natural Cycles, received 510(k) clearance from the US Food and Drug Administration (FDA) for its use of wrist temperature data from Apple Watch.
The integration will allow the Natural Cycles app, an FDA Cleared Class II medical device in the US, to use overnight wrist temperature data from Apple Watch (Series 8 and later and all models of Apple Watch Ultra) for users consenting to share this information.
Its use with Apple Watch has also been cleared by European regulators and registered for use in Australia.
The Natural Cycles app is used to prevent and plan pregnancy naturally without hormones. There are six days each cycle a woman (and people who have periods) can become pregnant, and the app is powered by an algorithm that analyzes daily hormone-driven temperature changes to confirm if the user is fertile that day or not.
Users manually take their body temperature with a thermometer or sync temperature data from an integrated wearable device upon wakening to receive their temperature-powered daily fertility status.
Tech meeting consumer demand
While Apple introduced temperature-sensing capabilities to Apple Watch from September 22 with a two-sensor design enabling users to receive retrospective ovulation estimates and improved period predictions, Apple's Cycle Tracking experience is not intended to be used as a form of birth control. This is where Natural Cycles steps in.
According to Natural Cycles co-founder and CEO Dr. Elina Berglund Scherwitz people began asking for integration so the team began clinical evaluations to validate the quality of the wrist temperature data to determine whether they could deliver Natural Cycles birth control using data from Apple Watch.
"We were thrilled with the results, submitted them to the FDA, and with this clearance are excited to give our users the ability to seamlessly measure using a device many already own and love.
And at a time when birth control accessibility has never been more important, we're excited to give millions of women who already own a supported Apple Watch access to deeper fertility insights."
Hormone monitoring is not foolproof
It's worth stressing that contraceptive pills, condoms, and temperature monitoring are NOT foolproof ways to prevent pregnancy. Natural Cycles faced investigation in 2017 in Sweden when over 660 people who used the app reported unintended pregnancies between January and June according to a report released by the Swedish Medical Products Agency, known in Swedish as Läkemedelsverket.
According to the FDA in 2018, clinical studies to evaluate the effectiveness of Natural Cycles for use in contraception involved 15,570 women who used the app for an average of eight months.
The app had a “perfect use” failure rate of 1.8 percent, which means 1.8 in 100 women who use the app for one year will become pregnant because they had sexual intercourse on a day when the app predicted they would not be fertile or because their contraceptive method failed when they had intercourse on a fertile day.
However, the app had a "typical use" failure rate of 6.5 percent, which accounted for women sometimes not using the app correctly by, for example, having unprotected intercourse on fertile days.
Securing the privacy of health data
The erosion of Roe v. Wade and reproductive rights in large chunks of the US means that the privacy and security of women's birth control data has never been more important.
As part of this FDA 510(k) review process, Natural Cycles demonstrated that its app complies with the new cybersecurity requirements of the Federal Food, Drug, and Cosmetic Act (FD&C Act). The company launched NC° Secure, a comprehensive privacy protection program earlier this year.
Natural Cycles co-founder and CEO Dr. Raoul Scherwitzl shared:
"Medical device regulations were established to keep users safe and we continue to be impressed with the FDA's thoroughness and ability to adapt in a rapidly changing digital health environment, including their increased focus on cybersecurity, which is of utmost importance for all digital products, especially within women's health."
Users must explicitly choose to share overnight wrist temperature data measured by Apple Watch from the Apple Health app with the Natural Cycles app and can manage permissions at any time.
Users can also choose which data from the Natural Cycles app, if any, they'd like to share to the Health app. Once in the Health app, a user's data is securely stored, and the user is in control of who can access their data.
Natural Cycles has raised $44.5 million in funding.
Lead image: Natural Cycles. Photo: Uncredited.