Menstruation is a well-known physiological phenomenon, and the menstrual cycle is associated with changes in body temperature. During the menstrual cycle, a woman’s body temperature varies from high to low, often slightly lower in the first half of the menstrual cycle and slightly higher in the second half. In addition to ovulation, the ovaries also secrete hormones, mainly estrogen and progesterone. Before ovulation, the growth and maturation of the follicles is the main focus of estrogen secretion. After ovulation, the follicles form the corpus luteum, which produces two hormones, estrogen and progesterone, and progesterone stimulates the body temperature center, causing the body temperature to rise slightly. People can measure the change of body temperature by checking the basal body temperature. The method of menstrual cycle and body temperature change is to measure the body temperature by oneself before waking up after a longer sleep of more than 6-15 hours and before any activity, and to record the measured body temperature on the basal body temperature sheet after waking up, day by day, and draw a curve. The normal curve is slightly lower before ovulation and lowest during ovulation; after ovulation, the body temperature is higher than during the follicular phase due to the thermogenic effect of progesterone. Therefore, the normal curve is biphasic, while the anovulatory menstrual cycle lacks progesterone without the above-mentioned regular changes, and the body temperature is consistent with the uniphasic type. I. Basal body temperature (BBT) measurement methods: 1, equipped with a thermometer, master the meter reading method, to ensure accuracy. It is recommended to use a special basic thermometer, basic thermometer and general thermometer is different, it is more accurate. Currently commonly used female basic thermometers generally do not use mercury-containing thermometers, most use safer electronic thermometers, the accuracy is generally ± 0.05 ℃. Electronic thermometer by the LCD screen directly display the measurement results, at a glance digital reflect the measured temperature, sensitive and clear, no need to bother to observe the mercury thermometer on the subtle scale, but also to protect the accuracy of the measurement results. 2.Every night before going to bed, the mercury column of the thermometer will be dumped to below 35 degrees, if it is an electronic thermometer will become the initial value, placed in the place within reach after waking up. 3.Every morning immediately after waking up, put the thermometer under the tongue for 5 minutes and then take out the reading and record it on a special form. It can also be measured under the armpit, but generally the armpit temperature is not as stable as the oral temperature. 4.It is strictly forbidden to get up, urinate and defecate, eat and talk before measuring the temperature. 5, should record the presence of many factors that affect the basal body temperature, such as: colds, insomnia, alcohol, medication, emotions, etc.. In case of cold, fever, diarrhea, insomnia, alcohol consumption, use of electric blankets, excessive alcohol consumption, late sleeping and late waking, etc., it is often easy to affect the basal body temperature, which should be noted when measuring, while taking care to mark special instructions. 6.The day of menstruation and intercourse must be marked with additional marks. 7, the measurement results recorded in the basal body temperature table, in addition to recording on paper, it is best to record in the special basal body temperature management tool, can be more convenient, intuitive view of the basal body temperature curve, at a glance to see the low temperature period and high temperature period. Second, the role of basal body temperature 1, to determine whether ovulation guidance contraception General follicular phase basal body temperature of 36.5 ℃, luteal phase rose more than 0.5 ℃, thus appearing biphasic performance, indicating ovulation, if the monophasic type without late rise in the temperature curve, suggesting no ovulation, its accuracy rate of 70% to 80%. If the body temperature increases by 0.3-0.6℃ or even more within 24 hours, then it indicates a state of ovulation. In addition, the basal body temperature is also a good indicator of the quality of the ovum. If the basal body temperature is high for a long period of time, lasting 13 to 14 days, then the quality of the eggs is good. 2. Diagnose early pregnancy and determine the risk of early pregnancy If the basal body temperature is high for more than two weeks, you should consider going to the hospital for a check-up because you may be pregnant. If ≥20 days can be determined as early pregnancy. Gradual decrease of BBT curve in early pregnancy indicates luteal insufficiency or placental malfunction, and the tendency of miscarriage. 3.Observation of luteal function BBT should rise immediately after ovulation and continue at a high level for ≥11 days. If BBT rises in a stepped pattern, the curve takes 3 days to reach a high level or BBT rises steadily for <11 days, luteal phase defeot (LPD) can be diagnosed. 4, suggesting other pathologies BBT does not decrease during menstruation, there may be endometriosis or early subclinical miscarriage, and endometriosis lesions bleed and produce absorption heat. Uterine amenorrhea should be considered when primary amenorrhea patients have biphasic BBT, such as congenital absence of uterus or endometrial destruction by tuberculosis of the reproductive tract. 5.Projecting the appropriate time for endometrial biopsy Patients with irregular cycles, to understand whether the endometrium has a secretory response and the function of the corpus luteum, endometrial biopsy should be performed 2 to 3 days before the estimated next menstrual flow after the rise of BBT. Third, the method of recording basal body temperature The measured basal body temperature is correctly recorded on the temperature record sheet, which can reflect the function of the ovaries. If it is not recorded correctly, it will lose its significance. Below is a graph of basal body temperature in a normal woman of childbearing age during a menstrual cycle. As seen in the graph, the first half of the body temperature is low and the second half of the body temperature is elevated, showing a typical biphasic temperature curve. This temperature curve indicates that the ovaries are ovulating, and the junction of the high and low temperature curves is the ovulation date of the ovaries. The vertical axis of the graph indicates the degree of body temperature, with each small cell being 0.1°C. The horizontal axis indicates the date and the day of the menstrual cycle, with each small cell being one day. Starting from the first day of menstruation, the measured temperature is plotted with dots in the corresponding grid of the temperature record sheet every day until the day before the next menstruation.