Week 01: Your pregnancy
What’s happening with you
This week is your menstrual period. If you become pregnant two weeks from now, this will be the point from which your pregnancy will be dated. Pregnancy is timed this way because most women don't know the precise moment they have ovulated or conceived. But most do remember the first day of their last menstrual period.
The pregnancy timetable
Pregnancy is based on a 40-week schedule. The first week is your period, and the very end of the second week marks the release of the egg—ovulation. The egg is fertilized during the third week. This means that using this dating method, you actually get pregnant on the third week.
You can calculate your due date by adding seven days and subtracting three months from the first day of your last period. You can also try this due date calculator from the American Pregnancy Association:
Pregnancy Calculator