How doctors confirm the due date, mainly from three aspects, many people do not know in the third aspect, many people do not know

Many mothers find it strange. Why is the due date of the doctor calculated different from themselves? Isn’t the due date starting from the day of the same room?

Some mothers said that I checked the Internet on the Internet: From the first day of menstruation, plus 280 days, but the due date with the hospital is not right.

How does the doctor calculate the due date?

Let’s first confirm a few key concepts:


This October is not based on the ten months on our calendar, but for 28 days of the surroundings as one month, and in October, the pregnancy is 280 days pregnant.

At the beginning of the due date

Many people think that the day of the same room, in fact, when the woman’s body is far away, the woman’s body is preparing for the secretion of eggs. These times should be calculated, so it should be the first day of the last menstrual tide.

Calculation of pregnancy weeks:

In order to more accurately calculate the due date, it is generally necessary to determine three times.Therefore, the due date given by the doctor is not the same as the calculation of themselves.

For the first time, it is usually around six weeks. We go to the hospital for the first birth checkup, usually to determine whether there is a pregnancy.

The doctor will ask the mother’s menstruation last day.

Some people can accurately tell doctors who come to a menstrual period, and some people may not be sure.

Therefore, it is recommended that women pay attention to their own physiological period. You can use some apps or make a mark on the calendar and mobile phone’s remarks, which is conducive to accurately knowing your due date, or discovering some abnormal phenomena of your body.

Because the menstrual rules of different women are different, some are 28 days for one menstrual cycle, and some are 30 days as one cycle. Some are 35 days and one cycle.Come, cannot be sure.

So not everyone can use this method to calculate.

Generally, doctors will not add 280 days on the first day of a simple menstrual period, but calculate through the increase and subtraction of the year, month, and day. Of course, most hospitals will have a turntable that calculates the due date, and it will come out twice.

For example, on the first day of menstruation in July 1, 2018, the due date is 1 year, in 2019, menstruation decreases 3, April, the date plus 7,8th, the due date is April 8, 2019.

This time is relatively rough.

The second time is about six weeks (this time, not every mother will do it)

Through the B -ultrasound (may be vaginal B -ultrasound), it is determined to be pregnant, and at the same time, see whether it is normal or ectopic pregnancy.

If you do the B -ultrasound in the abdomen, you may not be able to see it clearly because of the abdomen.

Therefore, some hospitals recommend doing vaginal B -ultrasound. In the vagina, from the vagina, it is closer to the uterus, and then you can observe the condition of the fetal heart sac.week.

The third time is to finally determine the due date when doing NT inspection

The NT test is to use the thickness of the transparent layer of the fetal neck of the fetus from the 11 weeks of 11 weeks-13+6 weeks to determine the risk of Tang’s syndrome through this thickness.

And to determine the size of the pregnancy week through the size of the fetus to determine the final due date.

Therefore, the calculation of these three due date may be the same, or it may be the error of one or two weeks before and after.

The due date for our own calculation may be the same as the doctor calculated, and it may not be the same.

Did you calculate accurately at that time?

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