Is it normal for the fetus to be one month larger than the actual gestational age?

Patient's question:

No

Doctor's answer:

The method of calculating the estimated due date from the last menstrual period is to start from the first day of the last menstrual period, subtract 3 months or add 9 months, and add 7 days. (If it is the lunar calendar, it needs to be converted to the Gregorian calendar. If calculated according to the lunar calendar, the month remains the same, and the day is changed to add 14, and it is the estimated due date.)