Samsung Electronics is adding temperature-based menstrual cycle tracking to the Galaxy Watch 5 series following a deal with Swedish firm Natural Cycles.

Samsung has also led a $7m investment round into Natural Cycles, a women’s health company specialising in the cycle tracking and birth control space

This will be the first time Natural Cycles’ algorithm has been adapted for a smartwatch. This partnership combines Samsung’s sensor technology with Natural Cycles’ fertility technology to give users more detailed insight into the wearer’s menstrual cycle.

Galaxy Watch 5 users will be able to access cycle tracking through a feature that was recently approved by the Ministry of Food & Drug Safety (MFDS) in South Korea. The cycle tracking feature has also been registered with the US Food & Drug Administration (FDA) and complies with CE Marking requirements.

“As a company that’s grounded in science and technology, we are excited to partner with Samsung to deliver a premium experience that pushes women’s health forward,” said Raoul Scherwitzl, co-CEO of Natural Cycles. “The Natural Cycles app has helped millions of women around the world take control of their fertility and this partnership will allow Samsung to leverage our fertility technology to offer temperature-based cycle tracking through a smartwatch for the first time.”

Natural Cycles says it is committed to pioneering women’s health with research and passion, leading the development of fertility technology. It developed the world’s first app that is powered by a proprietary algorithm that uses body temperature and other key fertility indicators to determine each user’s fertility status. Natural Cycles leverages its technology and algorithm to power the cycle tracking feature available on the Samsung Health app with the Galaxy Watch 5 series.

The investment round also included contributions from Natural Cycles’ existing investors Heartcore Capital, Headline, Bonnier Ventures and EQT Ventures.

Samsung’s infra-red temperature sensor lets users get a more detailed overview by tracking skin temperature changes as well as their menstrual cycle. The temperature sensor uses infra-red technology for more accurate readings, even if there is a temperature change in their surroundings or they move while sleeping. With all data encrypted and stored on the user’s device itself, it aims to give users more control of their health data and better peace of mind.

“Consumers can now easily track their menstrual cycle right from their wrist, combining Natural Cycles’ innovative fertility technology with Samsung’s superior temperature sensor to provide a more holistic understanding of their health and wellbeing,” said Hon Pak, vice president at Samsung Electronics. “This is another demonstration of Samsung’s open collaboration philosophy with other industry leaders to create better health experiences.”

The temperature sensor comes from Belgian microelectronics engineering company Melexis. The non-contact MLX90632 temperature sensor has applications in sport, health and other domains. Many companies have tried contact sensors that require tight touch of the watch with the skin for accurate data gathering. This is difficult to achieve in real life applications, leading to potentially unreliable data. “We are excited that our infra-red temperature sensor helps Samsung open up a world of new possibilities,” said Damien Macq, vice president of Melexis. “We miniaturised the MLX90632 for integration within wearable health devices. The Galaxy Watch 5 series is the first mass-market smartwatch to provide built-in, accurate, non-contact temperature measurement for personal health monitoring. We are making accurate skin thermometry the next go-to feature in th