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Natural Cycles Gets FDA Clearance to Use Apple Watch Temperature Data


The FDA has cleared the Apple Watch for use 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 is Natural Cycles’ second FDA-approved wearable integration, the first being the Oura Ring.

The Apple Watch integration is a big deal, considering it had around 30% of the global smartwatch market in 2022, which is also the year Apple introduced temperature sensors on the Series 8. While far from the first smartwatch to do so, Apple’s take was unique in that it incorporated two temperature sensors. One was located just under the screen, while the other was closer to the skin. The first aims to take ambient temperature measurements to help eliminate environmental biases. The sensors also allowed Apple to include advanced cycle tracking with retrospective ovulation estimates.

The Natural Cycles app requires users to enter daily temperature data – from a basal body temperature thermometer, free with a subscription if you don’t have a compatible wearable – which is then fed into an algorithm that supposedly inform users of their fertility. Status. It is currently the only digital birth control app approved by the FDA and designated as a Class II medical device. Class II devices are those defined as posing moderate to high risk to the user and include items such as blood pressure cuffs, contact lenses, and smart watch ECG features used to detect atrial fibrillation. Popular period tracking app Clue had also received FDA clearance as a contraceptive in 2021, but has since suspended that functionality.

In a statement, Elina Berglund Scherwitzl, co-founder and CEO of Natural Cycles, said the company has received many requests from users wanting to have an Apple Watch integration once the Series 8 launches with the new temperature sensors. Older models of the Apple Watch do not include temperature sensors, nor do the SE models; only Series 8 and 9 and Ultra models are compatible with this feature.

The use of wearable temperature data for reproductive health tracking is a growing trend. Natural Cycles first researched “wearable birth control” in 2020 before receiving FDA clearance for the technology in 2021. It gained clearance for Oura Ring integration last year and , earlier this year, partnered with Samsung to adapt its advanced cycle tracking algorithm for the company’s Galaxy Watch Series 5 and 6 smartwatches. (Galaxy Watches, however, are not compatible with Natural Cycles’ birth control features.)

The Apple Watch Series 8 introduced temperature sensors enabling advanced cycle tracking. Older models of the Apple Watch do not include these sensors.
Image: Amelia Holowaty Krales / The Verge

That said, Natural Cycles is not without controversy. The FDA initially granted approval to the app for its digital birth control feature in 2018, but the decision sparked some backlash after the app was linked to 37 unintended pregnancies at a single hospital in Sweden . Additionally, reproductive health apps have come under increased scrutiny in the United States following the Supreme Court’s overturning of the ruling. 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 proof that the application complies with cybersecurity requirements for data confidentiality. In addition to the FDA, Natural Cycles says its Apple Watch integration has also received clearance from European regulators and has also been registered for use in Australia.

However, receiving regulatory approval does not mean these methods are foolproof. The benefit 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, this still requires consumers to adhere to the correct use of the app, and user errors can still lead to unwanted pregnancies.