(1) General calculation method Menstruation inverse algorithm: The calculation method of the expected date of delivery is to add 9 or subtract 3 to the month of the last menstrual period, and add 7 to the date.
For example, if the last menstrual period is July 9, the expected date of delivery should be calculated as follows: 7-3 = 4 (months), 9 + 7 = 16 (days), that is, the expected date of delivery is on April of the following year. January 16th. The time of last menstrual period refers to the first day of last menstrual bleeding.
The expected date of delivery is the date of expected delivery. In medicine, it is usually calculated in weeks, that is, gestational age. It is normal for the actual delivery date to be two weeks before or after the due date.
(2) Calculation based on the time of early pregnancy reaction: This method of calculating the expected date of delivery is generally used when pregnant women cannot remember the time of their last menstrual period or have irregular menstruation, lactation, or amenorrhea. It is used during pregnancy. Generally, pregnancy reactions appear around 6 weeks of amenorrhea. At this time, the estimated date of delivery is: the occurrence of early pregnancy reactions plus 34 weeks is the estimated delivery date.
(3) Calculation based on the time of fetal movement: Generally, pregnant women can feel fetal movement at 18 to 20 weeks of pregnancy, so the method to calculate the expected delivery date based on fetal movement is the occurrence of fetal movement Add the date to 20 weeks to calculate the approximate due date.
(4) Calculate the date of delivery through B-ultrasound examination: This is mainly done through B-ultrasound measurement of biparietal diameter (BPD), crown-rump length (CRL) and femur length (FL) Measure. Early pregnancy B-ultrasound is more accurate in estimating gestational age.
This article is provided by Baidu Reading and is excerpted from \”The First Three Months of Pregnancy – Pregnancy Preparation Period\” Author: Wang Liru