Child Development pages
Tips for Women in Labor
Calculating your Expected Due Date
Calculating your Expected Due Date is not a complicated calculation, even though it may appear to be a mysterious figure that midwives and doctors need complex formulas or tables.
The most common way of calculating your expected due date is to simply add 9 months and 7 days to the date of the first day of your last period.
For example, if your last period started on March 10th, your due date will be December 17th.
Pregnancy is counted as having begun from the last period, not at conception which is about two weeks later. This will give you a 40 week pregnancy, counting from the the date of the first day of your last period. So in fact, women on average only carry their child for 38 weeks.