4hw.com.cn: due date is an exciting and stressful time for pregnant mothers. Do you know how to budget the due date?
The expected date of delivery, i.e. the date when the pregnant woman is expected to give birth. As it is difficult to accurately determine the time of pregnancy, it is stipulated in medicine that the first day of the last menstruation is the first day of pregnancy, and the pre delivery period is about 280 days later, that is, the pregnancy is maintained for 40 weeks, equivalent to 10 months. The expected date of production can generally be calculated by the following methods:
1. According to the calculation of last menstruation:
The month of the last menstrual period 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 April 15, 2014, date 15 + 7 = 22, month 4-3 = 1, and the expected delivery date is January 22, 2015.
2. According to the date of fetal movement:
If pregnant women can not remember the date of the last menstruation, it can be calculated according to the date of fetal movement, which generally 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. 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, or add 38 weeks, from the day after ovulation.
4. According to B-ultrasonic examination, it is estimated that:
When doctors do B-ultrasound, the gestational age can be estimated and the expected delivery date can be calculated according to the measured fetal head biparietal diameter, head hip length and femur length.
5. Extrapolation from the time of onset of pregnancy vomiting:
Pregnancy vomiting generally occurs at the sixth weekend of pregnancy, i.e. 42 days after the last menstruation, which is predicted to 280 days as the expected delivery period.
6. Based on the height of the uterine fundus, it is estimated that:
If the date of the last menstruation is unclear, pregnant women can also 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 between 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 under the umbilicus with 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 on the 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 vast majority of pregnant women will make corresponding arrangements according to their due date, but in fact, the due date is only a approximate time, not an accurate delivery date. It is difficult to determine the time of ovulation and conception for women with irregular menstrual cycle. Only about half of pregnant women will give birth on the day of expected delivery.