When transitioning from one measuring device to another, you may notice that the temperatures differ between the different devices.
It’s expected that the absolute temperature values will differ between different measuring devices as there can be a small difference in how each one measures. However, these differences don’t affect the accuracy of the NC° algorithm or the device itself.
When you switch to using a new device in the Natural Cycles app (under the top menu > My device > Change device), the algorithm will no longer use the temperature data from your old device, meaning that temperatures from different devices will not be mixed. In particular, temperatures from a thermometer and temperatures from a wearable device are not mixed because thermometers measure basal body temperatures while wearable devices measure distal skin temperatures which are fundamentally two different temperatures that 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:
Switching measuring devices
If you decide you want to switch devices, there’s 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 also should never use two measuring devices simultaneously (either two of the same kind or two different kinds). You can read more about this here.