Over the course of your menstrual cycle, your core body temperature dips slightly. Your core body temperature is lower during the follicular phase compared to the luteal phase of your cycle, and a sustained shift in temperature (0.4 to 0.6 degrees Fahrenheit) indicates ovulation has occurred. Planning intercourse to sync with this sustained shift in body temperature (when you are most fertile) is called timed intercourse. This can be accomplished by charting your basal body temperature (BBT) which is taken at the same time each morning before getting out of bed.
Your expected ovulation may also be monitored in two to four office visits. These visits consist of hormone levels and sonograms. When ovulation is expected, you will be instructed on the ideal days to engage in sexual intercourse.