When women go to the gynecological clinic for menstrual regulation, seeking children, or consulting on contraception, they all have the experience that the doctor will suggest you to take your basal body temperature. You may wonder why the basal body temperature is taken for different purposes. What is basal body temperature? Basal Body Temperature (BBT), also known as resting body temperature, is the temperature measured after 6-8 hours of sleep, for example, in the morning after waking up naturally, before the body temperature is affected by exercise, diet or emotional changes. Basal body temperature is usually the lowest body temperature of the body over the course of a day and night. The Physiology of the People’s Health Publishing House describes basal body temperature in this way: the body is awake and very quiet, not affected by muscle activity, mental tension, food and environmental temperature and other factors is called the “basal state”, the body temperature in the basal state, is called “basal body temperature “It is usually measured in the morning before waking up. The basal body temperature of women varies with the menstrual cycle, and is lower during the follicular phase, lowest on ovulation day, and rises 0.3-0.6°C after ovulation. How to determine the basal body temperature? 1, get a thermometer, master the meter reading method, to ensure accuracy. Most of them use safer electronic thermometers, with a measurement accuracy of ±0.05℃ and a resolution of 0.01. Accurate electronic thermometers display the measurement results directly from the LCD screen, reflecting the measured temperature digitally at a glance, more sensitive and clearer, without the need to observe the subtle scale on the mercury thermometer. It also guarantees 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 ℃, if it is an electronic thermometer will become the initial value, put it in the place within reach after waking up. 3.Every morning after waking up, immediately put the thermometer under the tongue for 5 minutes and then take out the reading and record it on paper. 4.It is strictly forbidden to get up, urinate, 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, drinking alcohol, use of electric blankets, excessive alcohol consumption, late sleeping and late waking, etc., often easily affect the accuracy of the basal body temperature, after measurement need to pay attention at the same time to be specially marked instructions. 6, the onset of menstruation with xxxxxx indicated, the day of intercourse with O marked. 7, the measurement results recorded in the basal body temperature table, can also be recorded on paper, the best 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. 8, the method of measuring basal body temperature, although simple and economical, but strict requirements, but also need to adhere to long-term. It usually requires more than 3 consecutive menstrual cycles to be measured to indicate the problem. What is the principle of basal body temperature? The basal body temperature of normal women of childbearing age varies cyclically, as does the menstrual cycle, and this temperature change is related to ovulation. The length of the menstrual cycle varies from person to person, ranging from 21-35 days, with an average of about 28 days, separated by the day of ovulation, into the follicular phase before ovulation and the luteal phase after ovulation. The length of the follicular phase varies, but the luteal phase is fixed at about 14 days and the next two days. On the day after ovulation, the formation of corpus luteum by the ovaries and the secretion of progesterone will cause the body temperature to rise by about 0.3℃-0.5℃, resulting in a high and low body temperature change. The high temperature period lasts about 12-16 days (average 14 days). 1.If there is no pregnancy, the corpus luteum atrophies and stops secreting progesterone, the body temperature drops and returns to the basic line, and menstruation comes. 2.If pregnant, the corpus luteum is supported by embryonic secretion of chorionic gonadotropin (hCG), which transforms into the corpus luteum of pregnancy and continues to secrete progesterone, and the body temperature continues to be high. 3. If the ovaries are malfunctioning and there is no ovulation or corpus luteum formation, the body temperature will continue to be low. Can pregnancy be determined by basal body temperature? The basal body temperature usually rises with ovulation. During the first half of the menstrual cycle, the body temperature fluctuates between 36.3°C and 36.5°C. After ovulation, the body temperature moves to the second half of the menstrual cycle and rises compared to the first half, fluctuating between 36.8°C and 37.1°C. The rise in body temperature indicates ovulation, and after a high temperature period lasting about two weeks, the body temperature decreases again and then it is the turn of the monthly menstrual cycle. If you are pregnant, your basal body temperature will not drop, but will remain at a high temperature. The high temperature is due to the increased amount of hormones secreted by the ovaries after pregnancy. However, women with poor ovarian function or fevers caused by colds can affect the basal body temperature curve, so it is not 100% accurate. What is the function of basal body temperature? 1, to determine whether ovulation guidance contraception general follicular phase basal body temperature between 36.3 ℃ – 36.5 ℃, luteal phase rise 0.3-0.5 ℃ or more, and thus the appearance of biphasic performance, indicating ovulation, if the monophasic type without late rise in the temperature curve, suggesting that there is no ovulation, its accuracy rate of 70% – 80%. The basal body temperature can also give a good indication of the quality of the ovulated eggs. If the basal body temperature is high for a long period of time, lasting 13-14 days, then the quality of the eggs is good. 2. To 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. In early pregnancy the basal body temperature curve gradually decreases, indicating luteal insufficiency or placental malfunction, with a tendency to miscarriage. 3. Observation of luteal function Basal body temperature 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 the basal body temperature rises steadily for <11 days, it can be diagnosed as luteal insufficiency. 4. Suggesting other pathologies basal body temperature does not decrease during menstruation, there may be endometriosis or early subclinical miscarriage. Bleeding from the lesion of endometriosis produces absorption heat, so that the basal body temperature remains at a high level. Uterine amenorrhea should be considered when the BBT is biphasic in patients with primary amenorrhea, such as congenital absence of the uterus or endometrial destruction by tuberculosis of the reproductive tract. 5. Patients with irregular cycles, to understand whether the endometrium has a secretory response and the function of the corpus luteum, should have an endometrial biopsy 2-3 days before the estimated next menstrual flow after the basal body temperature rises.