Natural Cycles will detect your pregnancy as early as the most sensitive pregnancy tests.
After ovulation your temperature rises due to the release of the hormone progesterone. If conception occurred, progesterone continues to be produced to help the development of the fetus. Thus, you will see your temperature remain elevated for a longer period than the normal length of the luteal phase.
Example of a chart when a pregnancy is confirmed.
Natural Cycles recognizes that conception has occurred and will prompt you to take a pregnancy test for confirmation. Once you indicate a positive pregnancy test Natural Cycles will format itself to your needs. Instead of the daily fertility status, you will see what week you are in, countdown to how many days you have left in your pregnancy, conception and due date.
We recommend continuing to take your temperature during your first trimester. Natural Cycles will monitor your hormone levels and can detect if there are any inconsistencies or risks or miscarriage. The app will in that case notify you in your messages, so there's no need for you to worry.