Natural Cycles
The world's first FDA-cleared contraceptive app, reading daily fertility status with a temperature algorithm
Natural Cycles is currently one of the few apps FDA-cleared as a medical device usable for contraception. Relying on daily basal body temperature and an algorithm, it tells the user whether today is a fertile or non-fertile day.
Features and application scenarios
This app's core claim is a 'hormone-free contraception option.' Its algorithm doesn't assume everyone has a standard 28-day cycle but analyzes the user's own temperature-data changes to determine the ovulation timing — the official statement is that this can significantly lower the chance of receiving a wrong fertility status. Temperature can be entered manually with a basal thermometer or synced automatically via a compatible wearable, the latter greatly reducing the hassle of taking your temperature every morning. The product line covers different life stages: NC° Birth Control (hormone-free contraception), NC° Plan Pregnancy (conception), NC° Follow Pregnancy (pregnancy tracking), NC° Postpartum (postpartum recovery), and NC° Perimenopause. On the regulatory side, it has been FDA-cleared for over eight years and is certified in 35+ countries, with the official statement of over 6 million users worldwide. It must be honestly explained that the actual contraceptive effect of such 'fertility awareness methods' highly depends on whether the user strictly complies — on fertile days you must use other protection or abstain, and once not implemented, the failure rate rises noticeably, which is also where it has long been discussed. It uses a subscription; the official site doesn't directly list a price.
Suited to adult users who don't want to or can't use hormonal contraception and are willing to take their temperature daily and strictly follow the interpretation; equally suited to conception, pregnancy, and postpartum-tracking needs.
Main features
- FDA-cleared for contraceptive use, cleared for over eight years
- Reads daily fertility status from personal basal-body-temperature data
- The algorithm doesn't assume a standard 28-day cycle
- Supports wearable automatic temperature sync
- NC° Birth Control hormone-free contraception mode
- NC° Plan Pregnancy conception mode
- NC° Follow Pregnancy and NC° Postpartum
- NC° Perimenopause tracking
Common uses
- Hormone-free contraception
- Precisely grasping the fertile window when trying to conceive
- Tracking cycle recovery after stopping hormonal contraception
- Recording body state during pregnancy and postpartum
- Tracking hormonal changes in perimenopause
Key Features
- FDA-cleared for contraceptive use, cleared for over eight years
- Reads daily fertility status from personal basal-body-temperature data
- The algorithm doesn't assume a standard 28-day cycle
- Supports wearable automatic temperature sync
- NC° Birth Control hormone-free contraception mode
- NC° Plan Pregnancy conception mode
- NC° Follow Pregnancy and NC° Postpartum
- NC° Perimenopause tracking
Pros
- FDA-cleared, with a clear regulatory status
- Hormone-free, suited to those who can't or won't use medication
- Covers the complete needs from contraception, conception, and pregnancy to perimenopause
- Wearable integration lowers the hassle of daily measurement
Cons
- Contraceptive effect highly depends on the user strictly complying; imperfect execution raises the failure rate
- Fertile days still require other protection or abstinence
- Requires daily temperature measurement, hard to maintain for those with irregular routines
- Uses a subscription and the official site doesn't directly list a price
Use Cases
- Hormone-free contraception
- Precisely grasping the fertile window when trying to conceive
- Tracking cycle recovery after stopping hormonal contraception
- Recording body state during pregnancy and postpartum
- Tracking hormonal changes in perimenopause
Editor's Note
My attitude toward this app is: the tech deserves recognition, but read the marketing language carefully. 'An FDA-cleared contraceptive app' sounds very reassuring, but what it's cleared for is the algorithm's interpretation, not a guarantee you won't get pregnant — the latter half relies on the user actually executing daily. For suitable people it's really suitable; for unsuitable people, forcing it carries considerable risk. For this kind of product, honesty matters more than convenience. (This article is an information roundup, not medical advice; discuss contraceptive methods with a doctor.)
FAQ
Is using an app for contraception really safe?
Natural Cycles is indeed FDA-cleared, but it's a fertility awareness method, and its effect highly depends on whether the user strictly complies — on days marked fertile, you must use other protection. If you can't do this, the failure rate is significantly higher than the official perfect-use number. Discussing with a doctor before deciding to use it is advised.
Do I have to take my temperature every day?
Temperature data is the algorithm's foundation, and the more regular the measurement, the more reliable the interpretation. It can now be measured automatically during sleep via a compatible wearable, saving the manual morning step, but you still need a stable routine for it to be meaningful.
Can it be used in Taiwan?
The app itself can be downloaded and used in many countries, but FDA clearance is a US regulatory status and isn't equivalent to a Taiwan MOHW medical-device license. Before treating it as a contraceptive method, Taiwan users must first discuss applicability and risk with an OB-GYN and not decide based on the app's labeling alone.
