The FDA has authorized the use of the Apple Watch with Natural cycles, a digital birth control app. This means that Natural Cycles users who own an Apple Watch Series 8, 9, Ultra, or Ultra 2 can now import their temperature data from the watch instead of manually taking their basal body temperature each morning. This marks Natural Cycles’ second FDA-approved wearable device integration, the first being the Oura ring.
Apple Watch integration is a big deal, given that it remained roughly 30 percent of the global smartwatch market in 2022, which is also the year Apple introduced temperature sensors in the Series 8. While it’s far from the first smartwatch to do so, Apple’s decision was unique because it incorporated two temperature sensors. One was located just below the screen, while the other was located closer to the skin. The first is intended to take ambient temperature readings to help eliminate environmental bias. The sensors also allowed Apple to include advanced cycle tracking with retrospective estimates of ovulation.
The Natural Cycles app requires people to enter daily temperature data (from a basal body temperature thermometer, which is free with a subscription if you don’t have a compatible wearable device) which is then fed into an algorithm that aims to inform users about their fertility. state. It is currently the only digital contraceptive app in use approved by the FDA and designated as a Class II medical device. Class II devices are those defined as being of moderate to high risk to the user and include items such as blood pressure cuffs, contact lenses, and smartwatch electrocardiogram functions used to detect atrial fibrillation. The popular period tracking app Clue also received FDA approval as a contraceptive in 2021, but has since i paused that feature.
In a statement, Natural Cycles co-founder and CEO Elina Berglund Scherwitzl said the company received numerous requests from users to add an Apple Watch integration once the Series 8 was released with the new temperature sensors. Older Apple Watch models do not include temperature sensors, nor do SE models; Only Series 8 and 9 and Ultra models support this feature.
The use of wearable temperature data for reproductive health monitoring is a growing trend. Natural Cycles first pursued “wearable contraceptives” in 2020 before receiving FDA clearance for the technology in 2021. It gained clearance for the Oura Ring integration last year and earlier this year partnered with Samsung to adapt its algorithm for advanced cycle tracking for the company’s Galaxy Watch 5 and 6 series smartwatches. (Galaxy watches are not compatible with Natural Cycles contraceptive features, however.)
That being said, Natural Cycles is not without controversy. The app was initially granted clearance by the FDA for its digital birth control feature in 2018, but the decision received some backlash after the app was linked to 37 unintended pregnancies at a single hospital in Sweden. Additionally, reproductive health apps have received increased scrutiny in the US following the Supreme Court’s reversal Roe v. Wade in 2022.
Natural Cycles says that for this integration, it had to submit clinical evaluations to the FDA through the agency’s 510(k) review process, as well as evidence that the app meets cybersecurity requirements for data privacy. In addition to the FDA, Natural Cycles says its Apple Watch integration has also received approval from European regulators and has also been registered for use in Australia.
Still, receiving regulatory approval does not mean that these methods are foolproof. The advantage of using temperature data from wearable devices is that it can eliminate some user error by adding another layer of automation, as well as providing more consistent data. However, it still requires consumers to comply with the correct use of the app, and user error can still result in unwanted pregnancies.