The 'Natural Cycles' App Now Has a Smart Band to Track Your Temperature and Fertility

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Tracking symptoms of your menstrual cycle can be surprisingly effective at identifying when you’re likely to get pregnant. One of the best metrics to track is body temperature, which wearables can pick up on. The Natural Cycles app already works with your Apple Watch or Oura Ring, but now the company is launching its own smart band. 

As I noted in my CES fitness trends roundup, smart bands are having a moment. Whoop used to be the only major screenless tracking band out there, but we now have Amazfit, Polar, and may soon see Luna and Speediance fitness bands. Garmin has a sleep tracking band. And now, this band from Natural Cycles uses the same form factor for the simpler job of tracking temperature. 

What the Natural Cycles band does

Natural Cycles is a subscription-based app ($149.99/year) that uses temperature to estimate where you are in your monthly cycle. The concept is similar to other period-tracking apps, but the temperature data makes it a fertility awareness method, in contrast to the old fashioned “rhythm method” that was so error-prone. 

Temperature tracking isn’t unique to this app; I remember using the same idea many years ago when I was trying to get pregnant. I had to wake up at the same time every day and take my temperature first thing in the morning with a thermometer that had an extra decimal place of accuracy compared to standard drugstore thermometers. From there, I’d chart my temperature on graph paper, and when my temperature ticked up by about half a degree (and stayed there), I could pinpoint the day I had most likely ovulated.

Wearables track temperature data automatically, as you’ve noticed if you wear an Oura ring or another wearable with a temperature sensor. Natural Cycles already has partnerships with both Oura and Apple Watch. Whoop, for its part, can track temperature with its own band and provide ovulation estimates.

Natural Cycles previously offered a Bluetooth-enabled thermometer ($39.99) for people who don’t have an Oura ring or Apple Watch. Now, it’s introducing its own wearable band, in purple, with a sticker price of $129.99.

Most users will get it for less, though. Natural Cycles is including the band free with its  $149.99 annual subscription, and current members can add the band to their existing subscription at a 25% discount, making it $97.49. The company describes these as limited time offers. Anyone adding the band to a monthly membership would pay the full $129.99. 

Natural Cycles is a subscription, like Whoop, so after your first year of using the device ends, you’d still have to pay to renew your subscription. The device seems to be intended only for capturing nighttime temperature, so you wouldn’t need to wear it during the day. The downside is that it doesn’t capture fitness or other data, so it can’t replace a fitness tracker. 

If you want the most affordable device that does it all, consider an Apple Watch Series 8 ($178 refurbished) or newer, or an Apple Watch SE 3 ($239.99)—both of these have a temperature sensor and can work with Natural Cycles, but they are both more expensive than the Natural Cycles subscription itself.