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# How to calculate the due date of pregnancy? Accurate calculation method of pregnancy and childbirth

After pregnancy, many pregnant mothers will care about one time, that is, the day of unloading the cargo, that is, the day of pre delivery. There are many ways to calculate the expected date of delivery. Let me tell you today. So how to calculate the expected date of production? In fact, there is a formula for calculating the expected date of delivery. If you don't know the pregnant mother, you can pay attention to it.

The expected date of delivery, i.e. the date when the pregnant woman is expected to give birth. Due date is not the exact delivery date. Scientists have calculated that only about 53% of women give birth on the due date.

Next, let's see how to calculate the expected date.

Calculation method of pre production

(1) According to the calculation of the last menstruation: the month of the last menstruation date plus 9 or minus 3 is the number of months in the expected delivery period; the days plus 7 is the expected delivery date. For example: the last menstruation is February 1, 1985, month 2 + 9, date 1 + 7, expected date = November 8 (85 years). The last menstruation is April 15, 1985, month 4-3, date 15 + 7, expected date = January 22 (86 years)

(2) Calculate according to the date of fetal movement: if you can't remember the date of the last menstruation, you can calculate according to the date of fetal movement. Generally, fetal movement starts 18-20 weeks after pregnancy. The calculation method is: the first parturient is the day of fetal movement plus 20 weeks; the second parturient is the day of fetal movement plus 22 weeks. (3) Calculation according to the basic temperature curve: take the last day of the low temperature section of the basic temperature curve as the ovulation day, and calculate 264-268 days from the later of the ovulation day, or add 38 weeks.

(4) According to B-ultrasonic examination calculation: when doctors do B-ultrasonic examination, the fetal age can be estimated by measuring the diameter of the fetal biparietal, the length of the head and buttock and the length of the femur, and the pre delivery period can be calculated (this method is mostly used as B-ultrasonic examination diagnosis by doctors).

(5) Estimation from the beginning of pregnancy: reaction to pregnancy vomiting generally occurs at the end of the sixth week of pregnancy, that is, 42 days after the last menstruation, from which to 280 days is the expected delivery period.

(6) According to the estimation of the height of the uterine fundus, if the date of the last menstruation is unclear, we can roughly estimate the expected delivery period according to the height of the uterine fundus. At the end of April, the height of the uterus is in the middle of the navel and the upper edge of the pubis (10cm above the pubic symphysis); at the end of May, the bottom of the uterus is in the lower two transverse fingers (16-17cm above the pubis); at the end of June, the bottom of the uterus is flat with the navel (19-20cm above the pubis); at the end of July, the bottom of the uterus is in the upper three transverse fingers (22-23cm above the pubis); At the end of the eighth month of pregnancy, the middle of xiphoid and umbilicus at the bottom of uterus (24-25cm above the shame); at the end of the ninth month of pregnancy, the two transverse fingers at the bottom of xiphoid (28-30cm above the pubis); at the end of the tenth month of pregnancy, the height of the bottom of uterus returns to the height at the eighth month, but the abdominal circumference is larger than that at the eighth month. The algorithm of the test self-test is: add 9 or subtract 3 from the number of months of the last menstruation, and add 7 to the number of days. If it is calculated by the lunar calendar, the calculation method of the month is the same, and the day is changed to add 15.

For example: the last menstruation is February 1, 1985. The expected date of 1 + 7 is: --- = November 8 (85 years). The last menstruation is April 15, 1985. The expected date of 15 + 7 is: --- = January 22 (86 years). The expected date of 4 - 3 does not mean that the date is certain. It is only the approximate time. The birth within two weeks before and after the expected date is normal. Due date is also related to menstrual cycle. Generally, due date is one day later for each extra day of menstrual cycle.

For example, for a pregnant woman whose menstrual cycle is 29 days, the pre delivery period will be about 1 day later than the 28 day period, which is the introduction of the calculation formula of the pre delivery period. It is normal to give birth within two weeks before and after the pre delivery period. If born between 24-36 weeks of gestation, it is considered as premature (early delivery), while if born after the 42nd week, it is overdue (overdue delivery).