Basal body temperature is a good indicator of ovulation and is recommended to be taken consistently in patients with abnormal ovulation. Compared to ultrasound ovulation monitoring, self-testing basal body temperature is an easy and economical method. Method and precautions: 1. Place the thermometer under the tongue for more than 5 minutes after waking up in the morning without talking, getting up or moving. 2, throughout the day, human body temperature fluctuates, therefore, it is recommended to measure the basal body temperature at the same time of day, preferably at 6-7 am. 3.Record the temperature measured every day into a special record sheet, indicated by black dots, and connect two adjacent dots with a straight line. 4.Use ***** to mark the menstrual period as special. 5.If you have a cold or other conditions that affect your temperature, please mark the corresponding date.