Most pregnancies last around 40 weeks (or 38 weeks from conception), so typically the best way to estimate your due date is to count 40 weeks, or 280 days, from the first day of your last menstrual period (LMP). Another way to do it is to subtract three months from the first day of your last period and add seven days.

Why is pregnancy dated from last period?

If you were having regular periods before pregnancy, your doctor will calculate your due date based off of your last menstrual period. This goes back to the fact that in order to get pregnant, your body ovulated—or released an egg—roughly in the middle of your cycle and it was fertilized by sperm.

Can you feel anything when sperm meets egg?

Can you feel when an egg gets fertilized? You wont feel when an egg gets fertilized. You also wont feel pregnant after two or three days. But some women can feel implantation, the process in which the fertilized egg travels down the fallopian tube and buries itself deep within the wall of the uterus.