You are not pregnant for weeks 1 and 2. Wait what?!
Then why are they included in a 40week pregnancy? They are used to help calculate your due date. The typical way to calculate is by using the first day of your last menstrual cycle. Most women ovulate 2 weeks after the first day of their last period. Hence conception occurring in the 3rd week. There are some variances that can affect this such as length of period or an irregular period. An ovulation predictor kit can also help to pin point the date more accurately.
How to calculate:
1. First day of last period
2. minus 3 months
3. add 7 days.
Ta Da!! Due date