The principle of taking temperature to ovulate is that after a woman ovulates, the level of progesterone in her body increases, and progesterone can regulate the body temperature center, causing the body temperature to rise by 0.3-0.5℃. If a rise in body temperature of 0.3-0.5°C is detected during the process of temperature testing and remains at such a level, the rising phase indicates that the patient is ovulating. The test should be performed under absolute silent sleep for 6 hours, without eating or talking after waking up, after which the thermometer is placed in the mouth and the measured temperature is recorded. The temperature is recorded every morning and ovulation may occur when the temperature rises by 0.3-0.5°C.