A Word About Due Dates And Trimesters

After you announce your pregnancy, the first question you'll probably be asked is "When are you due?" At your first prenatal visit, your health care provider will help you determine an expected delivery date (EDD). Your EDD is 40 weeks from the first day of your last menstrual period (LMP). If you deliver on your EDD, your baby is actually only about 38 weeks old — that's because your egg didn't become fertilized until about 2 weeks after the start of your last menstrual period.

It's important to remember that your due date is only an estimate — most babies are born between 38 and 42 weeks from the first day of their mom’s LMP and only a small percentage of women actually deliver on their due date.

Another common term you'll hear throughout your pregnancy is trimester. A pregnancy is divided into trimesters:

* the first trimester is from week 1 to the end of week 12
* the second trimester is from week 13 to the end of week 26
* the third trimester is from week 27 to the end of the pregnancy