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Cycle and Ovulation
The world's most accurate Cycle & Ovulation Tracker
Confirms ovulation with over 90% accuracy and detects when it hasn’t happened.
Works for all types of cycles, from clockwork to unpredictable.
Predict up to 12 cycles and track changes in ovulation and cycle health.
A complete view of your cycle health over time
Cycle Flags™ : Your cycle's quietest signals, decoded
Discover unique cycle patterns that help reveal hidden clues about your reproductive health
powered by OvuSense™ technology
Powered by OvuSense™ Technology — backed by 15 years of fertility science. OvuSense is a clinically proven fertility tracking technology, CE and UKCA certified as a Class IIa medical device, and FDA registered in the US. Trusted by women in over 40 countries, it's trained on more than 260,000 real-world cycles to deliver medical-grade accuracy in predicting and confirming ovulation, even for irregular cycles, PCOS, or endometriosis.
A comprehensive view of your cycle at every stage
How we compare
See how Cycle and Ovulation Pro compare with other traditional trackers in the market.
Cycle & Ovulation Pro
Others
| Cycle & Ovulation Pro | Others | |
|---|---|---|
| Period prediction | ||
| Ovulation day prediction | ||
| Ovulation confirmation with over 90% accuracy |  | |
| Anovulatory cycle detection | | |
| Support for irregular and diverse cycles | | |
| Proprietary Cycle Flags™ | | |
| Predictions for your next 12 cycles | | |
| Global medical standards | | |
| HSA/FSA eligibility | |
Cycle & Ovulation Pro
Others
| Ultrahuman | Others |
|---|---|
| Period prediction | |
| Ovulation day prediction | |
| Ovulation confirmation with over 90% accuracy | |
| |
| Anovulatory cycle detection | |
| |
| Support for irregular and diverse cycles | |
| |
| Proprietary Cycle Flags™ | |
| |
| Predictions for your next 12 cycles | |
| |
| Global medical standards | |
| |
| HSA/FSA eligibility | |
| |
SCIENCE
Backed by research. Built for your cycle.
Impact of BMI, stress, and activity on menstrual cycle length and variability: insights from 4055 cycles of Ultrahuman Ring AIR users
How does heart rate and heart rate variability change over the day in men and women? A database analysis of Ultrahuman Ring AIR users
Modifying sleep tracking algorithms reveals specific sleep deprivation patterns in women: early findings from the Ultrahuman Ring AIR Ramadan Mode
Temperature-Derived Cycle Flags: Characterizing Menstrual Cycle Dynamics Using Ultrahuman Cycle Tracking & Ovulation (C&O Pro) Algorithm powered by OvuSense™
Listening In: Introducing the Ultrahuman Cycle Tracking & Ovulation Pro (C&O Pro) Feature Powered by OvuSense™
Your data is secure, private, and always under your control.
Start tracking your cycle today
Personalized insights for every phase of your cycle. Understand, optimize, and make informed choices.
Don’t have the Ring?
The Ultrahuman Ring tracks your fertility and cycle health with biomarkers like temperature, HRV, and RHR. Get yours to unlock the full suite of women’s health PowerPlugs.
Already have the Ring?
Great! Let’s set up your cycle tracking. Follow the link below to test it out and sync your ring for personalized insights.
Still got questions?
What is new in the C&O Pro PowerPlug compared to previously available C&O PowerPlug?
C&O Pro, powered by viO’s OvuSense™ technology, builds on the capabilities of the original C&O PowerPlug by adding clinically validated temperature-based ovulation confirmation and detailed cycle health insights. While both versions offer period and ovulation day prediction, C&O Pro goes further with:
- Support for irregular and diverse cycles
- Ovulation confirmation with over 90% accuracy
- “Possible Anovulation” detection
- Cycle Flags™ to highlight key ovulatory patterns and possible irregularities
- Class II medical device status in EU, UK, Canada and Australia and FDA clearance under product code LHD
- HSA/FSA eligibility in supported regions
Can I use C&O Pro for HSA/FSA reimbursement?
In supported regions, C&O Pro is eligible for HSA/FSA reimbursement. You can also export your cycle reports to share with your healthcare provider for ongoing care.
How do I understand my results?
Each cycle will display one or more flags (e.g., Ovulatory, Short Luteal Phase) along with a summary explaining what the flag means and how it may relate to your cycle health. You can tap on each flag in the app for detailed definitions.
Can I view or export my Cycle Report?
Yes. You can download a comprehensive analysis of your past 6 cycles. A PDF export option is available so you can share results with your healthcare provider. Your first report will be available to you after 30 days of activation.
What is the difference between ovulation confirmation and fertile window prediction?
Ovulation confirmation means verifying after it has happened that ovulation occurred in your cycle, usually by detecting a sustained rise in temperature or other biomarkers.
Fertile window prediction means estimating in advance the days you are most likely to conceive, based on your cycle history and real-time biomarker trends.
In short, prediction helps you plan ahead, while confirmation tells you what actually happened. C&O Pro both predicts and confirms ovulation.
Which regions is C&O Pro available in?
C&O Pro is available in Available in the United States, United Kingdom, Australia, Canada, and across the European Union. And coming soon in other regions.
The Ultrahuman Fertile Window feature provides educational information about menstrual cycle phases and potential fertility patterns to help women understand their body's natural rhythms. It is not intended for use as a contraceptive, a sole method to achieve pregnancy, a medical diagnostic tool, or a substitute for professional medical advice. Insights are based on individual biomarker patterns and statistical data, but cycle variations may occur, and actual fertility windows may differ. For medical advice, diagnosis, treatment, or guidance on fertility, conception, or contraception, consult a qualified healthcare provider.