How long does it take to give birth after becoming pregnant

Patient's question:

No

Doctor's answer:

The method for calculating the due date is: add 9 months (or subtract 3 months) to the month of the last menstrual period and add 7 days to the day. A full-term pregnancy is approximately 280 days (about 40 weeks). Delivering within two weeks before or after the due date is considered normal.