There is no change in body temperature before ovulation, just like normal body temperature. After ovulation occurs, there will be a corresponding increase in body temperature, which will rise by 0.3-0.5°C. Therefore, if you monitor your basal body temperature during ovulation, you can expect the time of ovulation. Some women do not have time to go to the hospital to monitor ovulation with ultrasound, so they can use a thermometer at home to monitor the basal body temperature to know the time of ovulation and to master the time of sexual intercourse to help improve the conception rate. If sex does not occur during ovulation or if sex does not cause pregnancy, the elevated basal body temperature will gradually decrease after ovulation is over and return to the woman’s normal level. The reason why the body temperature rises during ovulation is that the level of progesterone rises significantly after the follicles mature during ovulation, resulting in an increase in the woman’s basal body temperature.