How to calculate the expected date of delivery for ordinary pregnancies?

First, the calculation of gestational weeks starts from the first day of the last menstruation. Four weeks are counted as one pregnancy month, and ten pregnancy months total 280 days.

Under normal circumstances, for naturally pregnant women with regular menstruation and a cycle of 28 days, the expected date of delivery is predicted by adding nine or minus three months to the month of the last menstruation, and adding seven to the date.

For example, if the last menstruation is May 5, 2020, the expected date of birth is February 12, 2021.

For women with irregular menstruation, if ovulation is monitored, the last menstrual day can be calculated from the ovulation day. For example, the last menstruation is May 1, 2020, but the ovulation date is 5 

On the 28th of the month, the expected date of birth should start from May 14, 2020, and the expected date of birth should be February 21, 2021.

How to calculate the expected date of delivery for a "test-tube baby" pregnancy?

The last menstrual period can be calculated from the date of transfer, and seventeen days before the date of transfer (nineteen days for blastocyst) are calculated as the last menstrual day. For example:

Two day-3 embryos were transplanted on June 30, 2020 and pregnancy was achieved. Then the expected date of birth should be calculated from June 13, 2020, and the expected date of birth should be March 2, 2021

Day 0.

On June 30, 2020, two blastocysts were transplanted and a pregnancy was achieved. Then the expected date of birth should start from June 11, 2020, and the expected date of birth should be March 18, 2021.

It should be clear that the expected date of delivery is only a prediction and not an accurate date of delivery. If the fetal development indicators are normal, it is normal for delivery one to two weeks earlier or later than the expected date of delivery.