Skip to main content

Women’s health doesn’t just affect women, it also impacts their families. That’s why the addition of a body temperature sensor, specifically for cycle tracking, is so important.

The new body temperature sensor that arrived on Apple Watch Series 8 and Apple Watch Ultra, can help women better understand their health.

And it’s been a long time since wearable devices came along, most of which offer cycle tracking features that are just simple calendars.

Wearables offer the possibility of collecting biometric data passively and non-invasively. But so far, it hasn’t been widespread enough for female-only features.

Apple’s new body temperature sensor will incorporate new fertility features, including body temperature-based ovulation tracking. This will allow women to gain more practical experience in monitoring their reproductive and personal health.

How Apple Temperature Tracking Works

Body temperature changes have long been used to detect changes in basal body temperature – which occur due to hormonal changes during the ovulation cycle.

Historically, women who wanted insight into their cycle had to use a thermometer and a personal logbook.

With the Apple Watch Series 8, the Health app will provide retrospective estimates of ovulation using body temperature readings.

It incorporates two temperature sensors – one on the heart rate chart under the case and another on the screen surface. These measure external biases in temperature changes (like your hand under the blanket, for example) and your skin temperature.

First, the Apple Watch Series 8 will establish a five-day baseline. This means that it will determine your normal temperature – which varies between individuals.

Every five seconds while asleep, the Series 8 will measure wrist temperature, looking for deviations from your baseline.

It can then retrospectively alert on fertility windows, validate future window predictions, and alert women to menstrual cycle deviations, which can highlight serious issues like PCOS.

Results are displayed in the Health app and can easily be shared with a doctor or healthcare provider.

Changes in body temperature can also indicate other health issues, meaning the new sensor could have wider health uses too.

Privacy after Wade vs Roe

Apple's new female health tracker empowers women - under the shadow of Wade v Roe

In a post-Roe vs. Wade world, there are serious considerations for many women about privacy.

Many women have started deleting their third-party cycle-tracking apps for fear that the information will be used against them if they try to get an abortion in a US state where it’s no longer legal.

Apple tried to allay those fears, pointing out that all health and fitness data in Apple products is encrypted (so even Apple can’t read it) and protected with a passcode, Touch ID or Face. ID with two-factor authentication enabled.

The Apple Watch Series 8 heralds a great technological development for women who want to know when they are most fertile. Because when it comes to reproductive rights, knowledge is power.

It also marks a commitment to the evolution of women’s health solutions for the brand, putting the power in the hands of women when it comes to family planning.

Suzaan Sauerman is an expert in wearable technology and femtech. She created the first heart rate monitor headphones with a team from Jabra, designed the user experience for the first true wireless headphones for Bowers & Wilkins and smart jewelry for one of the biggest names.