In our clinic, we often ask patients with menstrual disorders and infertility to monitor their basal body temperature (BBT). Basal body temperature refers to the body temperature in the resting state, after 6-8 hours of sleep, before getting up, eating and talking. The basal body temperature can indirectly respond to ovarian function, that is, it can respond to the ovulatory function and luteal function of women of reproductive age. In general, the basal body temperature is in the low-temperature phase at the time of menstruation and even lower on the day of ovulation. After ovulation, due to the action of the ovarian corpus luteum, the body temperature rises in the low-temperature phase and continues until the next menstrual period, when the body temperature drops again. How to take the basal body temperature? 1, you need to have an ordinary thermometer. 2.Every night before going to bed, you need to shake the thermometer to below 36.0 and place it on the pillow. 3, every morning after waking up, do not get up, do not urinate or defecate, do not talk, do not smoke, do not eat premise, put the thermometer under the tongue, test 5 minutes. (It is better to measure at a fixed time every day, and to ensure 6-8 hours of sleep at night) 4.Record the body temperature every day and mark it in the table. 5.If you have sex, cold, fever, abdominal pain, vaginal bleeding, sudden increase of leucorrhea, all need to be marked in the table. 6.Use one table for each menstrual cycle, start recording from the left side of the table, and start with x table period, the table on the previous page can be used for three cycles, if there is no cycle that is recorded continuously. Basal body temperature 1, biphasic temperature curve: normal basal body temperature is biphasic, that is, the follicular phase for the low temperature phase, the luteal phase for the high temperature phase. The low-temperature phase lasts about 2 weeks, and the high-temperature phase lasts 12 to 16 days, with an average of about 14 days. From the day of ovulation to the next menstrual day, the body temperature rises by 0.3~0.5℃. Before the rise in temperature, there is usually a low point of temperature (some people may have none), and then a sharp rise in temperature. This kind of temperature curve before low and after high (low before ovulation and high after ovulation) is called biphasic temperature curve, which indicates ovulation of the ovaries. 2. Monophasic basal body temperature: It is called monophasic basal body temperature when the high temperature phase and low temperature phase cannot be clearly distinguished during the menstrual cycle. It indicates poor ovarian function and no ovulation. Clinical significance 1. Estimation of ovulation. Basal body temperature is difficult to accurately determine the day of ovulation, but it can roughly estimate the ovulation period, and the accuracy of predicting ovulation is about 84%. Ovulation usually occurs 1~2 days before the rise of body temperature or during the rise from the low temperature phase to the high temperature phase. Some people have a 0.3~0.5℃ drop in basal body temperature during ovulation, which is due to the high level of estrogen prompting an increase in acetylcholine, causing vasodilation and increasing heat dissipation; some people do not have a drop in body temperature. Some scholars found that 5% of ovulation occurs 1 day before the day of lowest body temperature, 22% on the day of lowest body temperature, 40% at the end of low body temperature, and 25% on the first day of high body temperature. 2. Guiding conception. Sexual intercourse on or within 24 hours before or after the estimated day of ovulation can easily lead to conception. 3. To understand the function of the corpus luteum. The basal body temperature should rise immediately after ovulation, and the high temperature should be maintained for 12~16 days, with an average of 14 days. If the luteal body function is normal, the high temperature phase can reach 12 days. Luteal insufficiency: The clinical manifestations are shortened menstrual cycle, or menstrual cycle within the normal range, but the patient is not easy to conceive or miscarriage in early pregnancy. The basal body temperature is biphasic, but the high temperature phase is too short, less than 12 days, especially less than 11 days; or low temperature to high temperature in a “step” slowly rising (more than 3 days); or the rise is low, the rise is less than 0.3 ℃; or the basal body temperature is unstable (high temperature phase fluctuations of more than 0.1 ℃); or a small amount of high temperature end Vaginal bleeding, all suggest luteal insufficiency. Luteal atrophy: prolonged menstrual period. Basal body temperature shows a slow decrease in the high temperature phase. The menstrual period is still high temperature phase temperature. 4. Combine with ultrasound to diagnose luteinization syndrome of unruptured follicles (LUFS). Follicular luteinization syndrome refers to the development of follicles without ovulation, but the granulosa cells undergo luteinization to secrete progesterone, and the basal body temperature shows biphasic. The diagnosis of non-ruptured follicular luteinization syndrome can be made by ultrasound detection of follicles that do not become smaller or larger during the hyperthermia period. 5. Diagnosis of early pregnancy. Basal body temperature continues to rise for 16~18 days (without HCG) suggesting possible early pregnancy; over 20 days, early pregnancy can be confirmed. Gradual decrease in basal body temperature during early pregnancy suggests luteal insufficiency and a tendency to miscarriage. 6.Indirectly understand ovarian function. In general, biphasic body temperature with ovulation, monophasic body temperature without ovulation, indirectly reflecting ovarian (reserve) function. 7.Other. Menstrual basal body temperature does not decrease, in addition to luteal atrophy, it may also be due to absorption heat after bleeding from ectopic lesions of endometriosis. Primary amenorrhea with biphasic basal body temperature should be considered uterine type amenorrhea, such as absence of uterus or tuberculosis destroying the endometrium.