"It's just the beginning": Natural Cycles launches NC° Perimenopause mode - and its first wearable, the NC° Band
The first FDA-cleared digital contraceptive app extends its evidence-based model into perimenopause
For over a decade, Natural Cycles has been known for transforming temperature data into insights about ovulation and fertility. Now, the app that made history as the first FDA-cleared digital contraceptive has launched NC° Perimenopause mode, powered by its new NC° Menopause Algorithm — extending its evidence-based model beyond fertility and into one of the least understood phases of women’s health.
“Perimenopause is a biological transition that can last up to ten years,” says Magda Armbruster, Head of Product at Natural Cycles.
“But there’s no single test that can confirm it. Hormones shift daily, so one-time lab results are almost meaningless. What we can do - and what the algorithm does - is track those changes continuously.”
To support this next phase, Natural Cycles is also introducing its first proprietary wearable, the NC° Band. Worn only while sleeping, it automatically captures overnight temperature data, replacing the need for a manual thermometer and giving users an alternative to devices such as the Oura Ring.
NC° Band is the company’s first move into hardware - one that could reduce reliance on third-party platforms and allow greater control over data accuracy and accessibility.
Why perimenopause is so hard to pinpoint
Perimenopause isn’t a single event but a progression through stages. Early on, progesterone begins to decline, shortening cycles and triggering heavier bleeding or sleep disturbances. Later, estrogen starts to fluctuate more dramatically, leading to irregular cycles, hot flashes, and mood swings. By late perimenopause, both hormones fall to low levels, and cycles may become months apart.
Because these shifts happen unevenly, many women don’t realise what’s going on - or are told they’re “too young” when they raise concerns. In a recent survey of nearly 5,000 Natural Cycles users over 40, more than 90% reported low to moderate knowledge of menopause, while four in five said they wanted more information and support.
“Women were telling us they didn’t know what was happening in their bodies,” Magda says.
“We realised we could help by doing what we do best - using data to make sense of complex hormonal patterns.”
How the NC° Menopause algorithm works
The new mode combines three data sources: cycle tracking, basal temperature trends and then the user’s own symptom logging to capture sleep, mood, concentration changes and more. This, Natural Cycles says, is a major leap beyond simple symptom checkers or questionnaires.
The algorithm analyses these patterns continuously to assess whether a user is likely in early, mid, or late perimenopause. It also adapts over time as more data is logged, dynamically updating its assessment of each user’s hormonal stage. NC° Perimenopause also offers a daily fertility status, powered by the proven NC° Fertility Algorithm, for those who are looking to prevent pregnancy and not using hormonal birth control or HRT.
The NC° Perimenopause model was trained and validated using data from a study involving around 500 women aged 40 and above. Participants logged daily symptoms, cycles, and temperatures over several months. The anonymised data was then analysed by Natural Cycles’ science team in Geneva, in collaboration with its medical advisory board and leading menopause specialist Dr Barbara Levy.
“What makes our approach unique is the combination of real-world user data and established clinical knowledge,” Magda says.
“We’ve mapped how hormonal patterns appear in temperature trends and symptom changes, so we can estimate where someone is in the transition with much more nuance than a static lab test.”
Evidence-based and inclusive by design
As with its contraceptive and fertility-tracking algorithms, Natural Cycles has grounded the new mode in peer-reviewed science - a distinction that sets it apart in a growing market of menopause-focused apps and supplements.
The NC° Perimenopause mode is designed to work for a broad range of users, including those on hormonal birth control or hormone replacement therapy (HRT), and those who no longer have cycles due to procedures or medical conditions.
“It’s not always possible to determine the exact stage in every case,” Magda notes.
“But we wanted to make it inclusive - to help women understand their symptoms and patterns, regardless of where they are.”
The app also encourages women to use their data as a conversation starter in clinical settings. Its new Cycle Report feature summarises logged symptoms and changes that can be shown to healthcare providers.
“We know that women in their 30s or 40s are often dismissed when they raise perimenopause concerns,” says Magda.
“We want to give them something concrete to bring to those conversations.”
From birth control to lifespan health
Natural Cycles’ move into perimenopause marks the company’s most significant evolution since its contraceptive launch in 2013. Founded by physicist Dr Elina Berglund Scherwitzl and Dr Raoul Scherwitzl, the company pioneered the idea that fertility could be understood through continuous, personalised data rather than medication or devices.
After becoming profitable in 2022, Natural Cycles has expanded steadily — launching postpartum support, integrating with wearables such as Oura and Samsung’s Galaxy Watch, and entering new markets including Brazil. Its $55 million Series C funding round last year helped accelerate development of new features and global reach.
Now, as has been the case for other big name apps such as Clue and Flo Health too, the company is effectively extending its relationship with users by another decade or more. By supporting women through perimenopause and beyond, it redefines lifetime engagement in femtech - a sector historically perceived as focused only on the reproductive years.
“This is a natural next step for us,” says Magda.
“Our mission has always been to empower women with knowledge about their own bodies — from the first period to the final one.”
The science continues
Natural Cycles will present early findings from its perimenopause study at the Menopause Society conference later this month, with further research planned.
“There’s a huge lack of data on perimenopause,” Magda adds.
“We want to collaborate with researchers to advance the science and change the conversation.”
For now, NC° Perimenopause mode and the NC° Band mark the beginning of a broader role for an app once known for preventing pregnancy: translating hormonal complexity into clarity and supporting women through every phase of their health journey.
As Magda explains:
“It’s just the beginning — there’s so much more we can do.”