Basal Body Temperature (BBT), also known as resting body temperature, is the body temperature measured after 6-8 hours of sleep, such as in the morning after waking up from a natural sleep, when the body temperature has not yet been affected by exercise, diet or emotional changes. Basal body temperature is usually the lowest body temperature of the day and night. How to determine the basal body temperature? 1.Prepare a thermometer, master the reading method, and strive for accuracy. Currently commonly used in women’s basal body temperature thermometer generally do not use mercury-containing thermometers, most of the safer electronic thermometer, the use of measurement accuracy of ± 0.05 ℃, resolution of 0.01 electronic thermometer, accurate electronic thermometer by the LCD screen directly display the results of the measurements, at a glance digital reflection of the measured temperature, more sensitive and clear, without the need to struggle to observe the mercury thermometer on the scale of the fine, also guarantees the accuracy of the results. It also guarantees the accuracy of the measurement results. 2.Every night before going to bed, the mercury column of the thermometer will be thrown to 35 ℃ or below, if it is an electronic thermometer, it will become the initial value, and put it in the place where you can reach after waking up. 3.Every morning after waking up, immediately put the thermometer under the tongue for 5 minutes after taking out the reading, and recorded on paper. 4. It is strictly forbidden to get up, urinate and defecate, eat and talk before measuring the temperature. 5, should record the presence or absence of many factors affecting the basal body temperature, such as: colds, insomnia, alcohol, medication, emotions and so on. In case of colds, fever, diarrhea, insomnia, drinking, use of electric blankets, drinking too much alcohol, sleeping late and waking up late, etc., it is often easy to affect the accuracy of the basal body temperature, and need to pay attention to the special marking instructions at the same time after the measurement. 6, the onset of menstruation with xxxxxx indicated that the day of coitus with O labeling. 7, the measurement results recorded in the basal body temperature table, can also be recorded 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. 8, the method of measuring basal body temperature is simple and economical, but the requirements are strict and need to be adhered to for a long time. Generally need to measure more than 3 consecutive menstrual cycles to illustrate the problem. What is the principle of basal body temperature? The basal body temperature of normal women of childbearing age is cyclical like the menstrual cycle, and this temperature change is related to ovulation. A woman’s menstrual cycle begins on the first day of her menstrual cycle, and the length of the cycle varies from person to person, ranging from 21-35 days, with an average of about 28 days, which is separated by the day of ovulation, and is divided 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 on and two days off. The next day after ovulation, the ovary forms the corpus luteum, which secretes progesterone, causing the body temperature to rise by about 0.3℃-0.5℃, resulting in a two-phase change in body temperature. 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 baseline, and menstruation occurs. 2.If you are already pregnant, because the corpus luteum is supported by the embryo’s secretion of chorionic gonadotropin (hCG), it transforms into the corpus luteum of pregnancy, continues to secrete progesterone, and the body temperature continues to be high. 3, if the ovary is not functioning well, there is no ovulation and no corpus luteum formation, the body temperature will continue to be low. Can pregnancy be determined by basal body temperature? Basal body temperature usually rises with ovulation. In the first half of the menstrual cycle, the body temperature fluctuates between 36.3°C and 36.5°C. After ovulation, the body temperature rises in the second half of the menstrual cycle, fluctuating between 36.8°C and 37.1°C. The rise in temperature indicates that ovulation has occurred, and the high temperature lasts for about two weeks, after which the body temperature decreases again, and then it is time to go back to the monthly menstrual cycle. If you are pregnant, your basal body temperature will not drop and will remain at a high temperature. The reason for this high temperature is that the amount of hormones secreted by the ovaries increases after pregnancy. However, women with poor ovarian function or fever caused by colds will affect the basal body temperature curve, so the accuracy is not 100%. What is the role of basal body temperature? 1, to determine whether ovulation guidance contraception general follicular period basal body temperature between 36.3 degrees – 36.5 degrees, the luteal phase rose 0.3 ℃ – 0.5 ℃ or more, and thus the appearance of biphasic performance, said that there is ovulation, if the monophasic type of temperature curve without a later increase, suggesting no ovulation, the accuracy of its 70% -80%. Basal body temperature can also be roughly seen in the quality of the discharged eggs. If the high temperature of the basal body temperature is longer, can last 13-14 days, then it means that the quality of the eggs is good. 2, diagnose early pregnancy and determine the early pregnancy safety and security if the higher basal body temperature lasts for more than two weeks, we should consider going to the hospital to check, because you may be pregnant. If ≥ 20 days can be determined as early pregnancy. The gradual decline of the basal body temperature curve in early pregnancy indicates that the luteal function is insufficient or the placenta is dysfunctional, and there is a tendency to miscarriage. 3, Observation of luteal function Basal body temperature (BBT) should rise immediately after ovulation and continue at a high level for ≥11 days. If the BBT rises in a stepwise manner and the curve takes 3 days to reach a high level or the basal body temperature rises steadily for <11 days, luteal insufficiency can be diagnosed. 4, suggesting other pathologies that the basal body temperature does not decrease during menstruation, there may be endometriosis or early subclinical abortion, the endometriosis of the lesion bleeding will produce absorption of heat, so that the basal body temperature is still at a high temperature level. When BBT is biphasic in patients with primary amenorrhea, uterine amenorrhea should be considered, such as congenital absence of the uterus or destruction of the endometrium by genital tract tuberculosis. 5. To estimate the appropriate time for endometrial biopsy in 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 after the basal body temperature has risen and estimated to be 2-3 days prior to the onset of the next menstrual period.