The body is awake and very quiet, not affected by muscle activity, mental tension, food and environmental temperature and other factors is the “basal state”, the body temperature in the basal state is “basal body temperature”. The basal body temperature of normal women changes with the menstrual cycle, and after ovulation, the body temperature increases by 0.3-0.5℃ and lasts until the next menstruation, which can indirectly reflect the ovarian function of women through the basal body temperature. The first thing you should do is to take your temperature and place the thermometer under your tongue and leave it there for 5 minutes to get the daily “basal body temperature”. If you can take your temperature early in the morning at a fixed time every day, it is better. The temperature for each day of the menstrual cycle is marked on the appropriate paper and curved to give the basal body temperature (BBT) chart your doctor needs. Each row of the BBT chart starts with the first day of a menstrual cycle and is recorded from the left side of the chart until the next menstrual period when the next row of the chart should be restarted. The amount of bleeding during the menstrual period can be recorded according to little, much or very much, using “.” , “x” and “x x”. Also, please indicate on the basal body temperature chart the day you had sex, vaginal bleeding, lower abdominal pain, medication, special examination and treatment, etc. Flu, insomnia, late sleep, alcohol consumption, etc. may also affect the accuracy of the temperature, so it is recommended that you also indicate this in the notes for reference.