You may notice a difference in the absolute temperature values when transitioning from one measuring device to another. This variance is expected and happens because each device measures temperature slightly differently. However, these differences do not affect the accuracy of the NC° algorithm or the device itself.
When you switch to a new device in the Natural Cycles app, the algorithm automatically stops using data from the old device. That is because data from different types of devices—specifically basal body temperatures (from a thermometer) and distal skin temperatures (from a wearable device)—are fundamentally different readings and should not be mixed.
It’s also important to keep in mind that the algorithm analyzes your temperature curve throughout your whole cycle to determine your daily fertility status. This means that the absolute temperature values on individual days don’t matter as much – what’s important is how your temperature curve develops during your cycle.
Natural Cycles is regulated as a medical device by the FDA in the US and CE-marked in Europe. The following measuring devices are intended to be used with Natural Cycles:
- The NC° Band
- The Oura Ring
- The Apple Watch
- The NC° Thermometer Gen1
- The NC° Thermometer Gen2
- The NC° Thermometer Gen3
Switching measuring devices
If you decide you want to switch devices (top menu > My Device > Switch device), there are a few things to keep in mind:
- For a better experience, we recommend only switching measuring devices at the start of a new cycle.
- Please keep in mind that you should avoid switching measuring devices too often - not only to stay in the habit of measuring with your chosen device but also because this may otherwise delay ovulation detection and cause more Red Days (NC° Birth Control) or Brown Days (NC° Plan Pregnancy).
- You should also never use two measuring devices simultaneously (either of the same kind or two different kinds). You can read more about this in the article: Can I use two devices at the same time?