How to calculate due date

We all know that most mothers have their own due date. The due date is different for different mothers' physical conditions and different baby development conditions, but the difference will not exceed ten days. Some people don't know how to calculate the due date. As we all know, it takes ten months of pregnancy to give birth. In fact, the normal pregnancy time of women does not reach ten months, so how to calculate the due date?

How to calculate the due date

1. Calculation method of the last menstrual period: add 9 or subtract 3 to the month of the last menstrual period, and add 7 to the day (the day refers to the first day of the last menstrual period).

For example: For example, the last menstrual period started on March 5th and ended on March 10th.

Then the due date is

Month = 3 + 9 = December

Date = 5 + 7 = 12th

So the due date is December 12th.

Applicable people:

This method is suitable for pregnant mothers who can clearly remember their last menstruation and have a normal menstrual cycle (about 28 to 32 days).

In fact, many due date calculators on the Internet, or due date calculation books issued by hospitals, all use this calculation method.

2. B-ultrasound data calculation method: Through B-ultrasound examination, measuring the baby's biparietal diameter, head circumference, femur length, abdominal circumference and other physical data of the baby (which is similar to the three measurements of adults), the expected date of delivery can also be calculated.

The following are the relevant B-ultrasound data. It doesn’t matter if pregnant mothers don’t understand it. Because the doctor will help you calculate the gestational age based on these data (the age of the fetus in weeks, generally the expected date of delivery is 40 weeks of gestational age), so you don't need to calculate it yourself. Generally, after the calculation, the doctor will write on the ultrasound report: gestational age ** weeks + * days.

GS—gestational sac: also called gestational sac, which is the small house that wraps the baby and amniotic fluid. Generally, 35 days after menstruation stops, the gestational sac can be seen in the uterine cavity through B-ultrasound. The diameter of the gestational sac is about 2 cm at 6 weeks of pregnancy and about 5 cm at 10 weeks of pregnancy.

FE—Embryonic bud: When the baby is not yet formed, it is just like a small bean that has just sprouted. Ultrasound can reveal the embryo at 6-7 weeks of pregnancy.

CRL—Crown-Rump Length: It is the distance between the baby’s head and buttocks, mainly used to determine the gestational age between 7 and 12 weeks of pregnancy. Estimated gestational age between 6 and 13 weeks (weeks) = crown-rump length + 6.5 (cm)