Why do pregnancies start counting from the last day of your period instead of the day of conception?

Question

Also, how accurate is the due date?

In: 801

Answer 1

Because it was at the time (and probably still is) nearly impossible to accurately tell the day of conception. Even if you only had one partner you had sex with one time, the actual date that the ~~spent~~ *sperm* fuses with the egg can lag by as much as a week.