How long does a woman calculate the exact duration of pregnancy?

Patient's question:

No

Doctor's answer:

Usually, it is calculated from the first day of the last menstrual period. The estimated due date also starts from this day, and 280 days of pregnancy is considered the gestation period. It is not necessary to calculate the specific time of intercourse or conception. As long as pregnancy is confirmed, the calculation of pregnancy duration begins from the first day of the last menstrual period.