There are signs which you can (but don't have to!) observe on your temperature chart that may signal the implantation of a fertilized egg in the uterus. Those are:
- A second increase in basal body temperature, observed around seven to ten days after ovulation.
- A singular fall of basal body temperature, lasting only one day, also occurring seven to ten days after ovulation.
Note: none of these are reliable indicators of whether you're pregnant. You may be pregnant and not experience these symptoms, or experience the symptoms and not be pregnant. The only reliable way to determine if you are pregnant is by taking a pregnancy test.