You should start your fertility charting to find out exactly when and if you ovulate and whether you had intercourse at the right time. Fertility or basal body temperature charting is done for several reasons.Why Chart?
Fertility or basal body temperature charting is done for several reasons:

1. To see when and if you ovulate
2. To calculate the cycle length
3. To assess if you made love at the right time
4. To diagnose a pregnancy early on
5. To evaluate your cycle for fertility problems
6. To see if your fertility medication was successful
7. To correlate other fertility signs such as cervical mucus or cervical position with actual ovulation on a BBT chart (see Other Signs below)
8. To calculate the follicular and the corpus luteum phases (a key to possible infertility issues)

More about this last point: You remember I mentioned that a biphasic curve has two phases: before and after ovulation. Charting not only helps you plot the biphasic curve, but you can measure the length of the two phases as well. If the second phase is too short (less than 12 days), this can cause problems with implantation of fertilized eggs. Fertility charting can help reveal such an issue.