Natural Cycles has secured its sixth U.S. Food and Drug Administration clearance for an updated digital contraception algorithm that blends statistical modeling with machine learning, according to company announcements. The updated NC° Fertility Algorithm predicts fertile and non-fertile days using tens of millions of real-world data points while adapting to individual menstrual cycle patterns.
“People don’t just want effective birth control; they want a method that fits naturally into their lives,” said Dr. Elina Berglund Scherwitzl, chief executive and co-founder of Natural Cycles, in an official statement.
Regulatory Milestones and Algorithm Updates
According to Natural Cycles, the updated system maintains the application’s established safety and effectiveness profile while increasing the frequency of “Green Days”—periods where the app confirms that pregnancy protection is not necessary. The software-based contraceptive maintains a 98 percent effectiveness rate when used as intended, and 93 percent effectiveness with typical use, placing it in the same category as the combined oral contraceptive pill, based on company data.
“As our scientific understanding of fertility grows and we continue to learn from more than a decade of real-world data, we can responsibly refine the technology through rigorous research, clinical validation, and FDA review,” Dr. Berglund Scherwitzl stated.
The latest regulatory decision follows a series of clearances spanning several years. The FDA granted the company its first De Novo clearance for the birth control app in 2018. Subsequent clearances enabled integration with the Oura Ring in 2021 and the Apple Watch in 2023. In 2024, the FDA cleared a Predetermined Change Control Plan, establishing a regulatory pathway for future hardware integrations, which subsequently facilitated the launch of the NC° Band and Garmin connectivity introduced in March 2026. A 2025 clearance permitted the app to be offered both over-the-counter and by prescription.
Hardware Integration and Personalization
The updated algorithm improves performance for individuals with irregular cycles and processes lower-quality temperature or biomarker data more effectively, according to company disclosures. A biomarker represents a measurable biological signal, such as body temperature, that provides information regarding internal bodily processes.
“The next chapter for digital contraception is making it more personalised and easier to use while maintaining the same high standard of safety,” said Dr. Kerry Krauss, senior medical adviser at Natural Cycles, in a company release. “This FDA clearance demonstrates how advances in AI and machine learning can improve the user experience while preserving the scientific rigour expected of a regulated medical device.”
Natural Cycles has filed a patent application covering key innovations within the updated algorithm. Beyond the United States, the company holds regulatory authorizations in more than eight markets worldwide, including Europe, Canada, Brazil, Australia, South Korea, and Singapore.
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