How to calculate the time of pregnancy

We often hear people discussing the size of the baby in a pregnant woman's belly, but when asked how to calculate the number of days of pregnancy, most people don't know. So, how should the number of days of pregnancy be calculated? Conveniently, pregnant women can calculate it by themselves, that is, look at the time of menstruation, find that the pregnancy is not wanted, how long can they get the vaccine?

How to calculate the number of days of pregnancy

The due date is just a scheduled time. About half of the pregnant women do not give birth on the due date. It is generally normal to give birth 3 weeks before or half a month after the due date. In fact, there are many ways to calculate the expected date of delivery, and pregnant mothers can calculate it independently according to their own conditions.

1. Calculate based on the expected date of delivery:

Add 9 or subtract 3 from the month of the expected date of delivery to get the month of delivery; add 7 to the day of delivery to get the day of delivery. For example: Ms. Chen's due date is March 13, 2008, and her due date is approximately December 20, 2008. Ms. Chen's due date was May 28, 2008, and her due date was approximately March 5, 2009. You can also calculate backwards from the first day of the due date to the 280th day, which is the due date.

2. Calculate based on the baby's fetal movement date:

If you can't remember your due date, you can calculate it based on the baby's fetal movement time. Generally, fetal movement begins between 18 and 20 weeks of pregnancy. The calculation method is: for primiparas, it is the day the baby moves plus 20 weeks; for multiparas, it is the day the baby moves plus 22 weeks.

3. Calculated based on the basic body temperature curve:

The last day of the ultra-low temperature segment of the basal body temperature curve is taken as the ovulation period, and 264-268 days are counted backward from the ovulation period, or 38 weeks are added.

4. Calculation based on B-ultrasound examination:

When doctors do B-ultrasound, they can measure the biparietal diameter of the fetal head, the brachiocephalic diameter and the length of the femoral head to estimate the gestational age and calculate the date of delivery (this method is mostly used by doctors for B-ultrasound examination and diagnosis).

5. Calculate from the time when morning sickness starts:

Morning sickness usually occurs on the 6th week of pregnancy, which is 42 days after the expected date of delivery, and then counting backwards to 280 days is the due date.