The expected date of delivery after pregnancy is a problem that we all pay more attention to. There are many ways to calculate the expected date of delivery. Let's talk about it today. So how to calculate the expected date of delivery? In fact, there is a formula for calculating the expected date of delivery. If you don't know about it, you can pay attention to it.
The expected date of delivery, i.e. the expected date of delivery. The expected date of delivery is not an exact date of delivery. Scientists have calculated that only about 53% of women give birth on that day.
Next, let's take a look at how to calculate the expected date of delivery.
Pre production calculation method
(1) According to the calculation of the last menstruation: add 9 or subtract 3 from the month of the last menstrual date to be the number of months in the expected delivery period; add 7 to the number of days to be the expected date of delivery. For example: the last menstruation is February 1, 1985, month 2 + 9, date 1 + 7, expected date of delivery = November 8 (85 years). The last menstruation is April 15, 1985, April 3, date 15 + 7, expected date = January 22 (86 years)
(2) According to the date of fetal movement: if you can't remember the date of the last menstruation, you can calculate it according to the date of fetal movement. Generally, fetal movement begins 18-20 weeks after pregnancy. The calculation method is: primipara is fetal movement day plus 20 weeks; multipara is fetal movement day plus 22 weeks. (3) According to the basal body temperature curve, the last day of the low temperature segment of the basal body temperature curve was taken as the ovulation day, and 264-268 days or 38 weeks were calculated from the ovulation date.
(4) According to B-ultrasound: doctors can estimate the gestational age by measuring the biparietal diameter of fetal head, the length of head and hip and the length of femur when doctors do B-ultrasound examination, and then calculate the expected date of delivery (this method is mostly used for doctors' B-ultrasound diagnosis).
(5) From the beginning of pregnancy vomiting time: reaction pregnancy vomiting generally occurs at the end of 6 weeks of pregnancy, that is, 42 days after the last menstruation. From this backward calculation to 280 days is the expected date of delivery.
(6) According to the height of the uterine fundus, if the date of the last menstruation is not clear, the expected date of delivery can be roughly estimated according to the height of the uterine fundus. At the end of April of pregnancy, the height of uterus is between the navel and the upper edge of pubis (10 cm above pubic symphysis); at the end of May, the bottom of uterus is under the umbilicus (16-17 cm above the pubis); at the end of June, the bottom of uterus is flat on the navel (19-20 cm above the pubis); at the end of July, the uterine floor is on the three transverse fingers above the umbilicus (22-23 cm above the pubis); At the end of the eighth month of gestation, the xiphoid process of the uterine fundus and the median of the umbilicus (24-25 cm above the pubis); at the end of September, the uterine fundus was 2 transverse fingers under the xiphoid process (28-30 cm above the pubis); at the end of the 10th month of pregnancy, the height of the uterine fundus returned to the height of the eighth month, but the abdominal circumference was larger than that of the eighth month. The algorithm of the expected date of delivery is: add 9 or subtract 3 from the last menstrual months, and add 7 to the day. If the lunar calendar is used, the calculation method of the month is the same, and 15 is added to the day.
For example: the last menstruation is February 1, 1985, the date of 1 + 7 is: --- = November 8 (1985) month 2 + 9 the last menstruation is April 15, 1985, the date of 15 + 7 is: --- = January 22 (86 years) the expected date of delivery is April 3, which does not mean that this date is definitely born, it is only the approximate time, and it is normal to be born within two weeks before and after the expected delivery date. The expected date of delivery is also related to the menstrual cycle. Generally, every day of the menstrual cycle, the expected delivery period is one day later.
For example, for pregnant women whose menstrual cycle is 29 days, the expected delivery period will be about 1 day later than that of the 28 day cycle. This is about the introduction of the calculation formula of the expected delivery period. Delivery within two weeks before and after the expected delivery period is normal. If the baby is born between 24 and 36 weeks of pregnancy, it is considered as premature delivery (early delivery), and the case that it is later than the expected delivery date, i.e. born after the 42nd week, is considered as overdue delivery (overdue delivery).