After ovulation, the basal body temperature rises, indicating that ovulation has already taken place and the corpus luteum is formed locally. The corpus luteum stimulates the body temperature center and therefore causes the basal body temperature to rise, which is often referred to clinically as bi-directional basal body temperature, indicating that ovulation has been completed. If you want to plan a pregnancy, you should have intercourse when the basal body temperature rises, because the egg survives for about 24 hours after ovulation, and the sperm reaches the fallopian tube in a maximum of 6 hours, so there is still a chance of pregnancy. Therefore, in clinical practice, monitoring the basal body temperature can tell the day of ovulation, and also whether the luteal function is normal, because a high temperature lasting less than 12 days after ovulation indicates insufficient luteal function.