What Is Basal Body Temperature?

Basal body temperature is described in "Physiology" of People's Medical Publishing House as follows: The state when the human body is awake and very quiet, and is not affected by factors such as muscle activity, mental stress, food and environmental temperature is called "basic state" The body temperature is called "basal body temperature", also called "resting body temperature", and is usually measured before getting up in the morning. The basal body temperature of women changes with the menstrual cycle. During the follicular phase, the body temperature is low, the ovulation day is the lowest, and it rises 0.3 ~ 0.6 after ovulation. ^[1]

Basal body temperature

People's Medical Publishing House

Since the basal body temperature change rule is generally reflected in the body temperature value after the decimal point, it is recommended to use a thermometer with an accuracy of at least ± 0.1 ° C to measure. Mercury thermometers are the most accurate. There are also some "basic thermometers" specially designed for measuring basal body temperature, which have functions of data storage and drawing tables, which are more expensive than ordinary electronic thermometers.

(Take the traditional sublingual measurement method after a morning rise provided by a famous domestic hospital as an example, in which the sublingual temperature measurement is more accurate than the underarm temperature measurement)

1. Prepare a basic thermometer or a smart thermometer in advance, and place it at your bedside or pillow where you can easily get it. The smart thermometer can be measured every morning.

2. After sleeping for more than 6 hours, put the thermometer into the mouth after waking up (please put the probe at the root of the underside of the tongue and close the mouth tightly to ensure that the correct temperature is measured.) At least 3 minutes (usually from 5 to 7 in the morning) , Take out the thermometer to observe the temperature, and mark the dot at the corresponding position in the form. Connect the small dots with line segments to form the basal body temperature curve.

3. Usually start measuring the body temperature on the 5th day of the menstrual cycle. During menstruation, pay attention to observe and record the menstrual flow; when the menstrual flow is moderate and normal, mark it with a cross ×; when the menstrual flow is large, record ××; When the amount is particularly small, use a period "," to mark it.

4. When you are in the room, add a circle to the body temperature dot and mark it as "", which is sexy (excited, orgasm). If you can reach orgasm, add "" above the ; if you have sexual excitement, you can't reach orgasm Add "" mark to ; if it is sexy and indifferent, add "" mark under .

5. When you are close to ovulation, pay special attention to the vaginal secretions. For those with a large amount such as runny nose and transparent brushed length (> 8cm), use 3 plus signs "+++" to mark the corresponding positions in the "Remarks" column. ; For those with a length of 5 ~ 8cm, mark "++"; For those with a small amount and turbid drawing <5cm, mark with "+".

6. might have

   Progesterone can excite the hypothalamic body temperature regulation center, which can increase the basal body temperature by 0.3 ~ 0.5 after ovulation, which can be used clinically as one of the signs to determine the date of ovulation. ^[3]

   • Response to corpus luteum function: The biphasic body temperature before and after the ovulation day as the boundary shows that the corpus luteum function is normal,

     Graph with normal ovulation

     The basal body temperature curve shows a standard high-low temperature biphasic change, that is, a biphasic body temperature. From the beginning of menstruation to the day of ovulation, the low temperature period is 14 days; after the ovulation, the high temperature continues for 14 days, of which the 14th day is the ovulation day.

     Basal body temperature curve for already pregnant

     The high temperature lasted from the 15th day to the 34th day, and it has lasted for 20 days.

     Basal body temperature curve for suspected early abortion

     The high temperature, which lasted for 20 days from the 15th to the 34th, decreased in temperature, indicating that she was pregnant, but early abortion may occur.

     Basal body temperature curve without ovulation

     Continued low temperature, no high temperature period, no high and low temperature biphasic changes.

     Luteal dysfunction

     If the basal body temperature drops slowly before the next menstrual period, it indicates that the corpus luteum is not functioning properly.

     Insufficient progesterone concentration causes slow rise in body temperature during ovulation

     It can be observed that after ovulation on the 14th, the temperature began to rise slowly on the 15th, suggesting that the progesterone concentration was insufficient.