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

The easiest answer is because it’s very, very rare to pinpoint the date of ovulation (the point at which an egg is released), and therefore conception. And that’s only if someone is trying with multiple methods. The majority of people do not know when they ovulate. Also, after ovulation, the egg can live for up to 24 hours. The variations cause too much confusion, so to maintain consistency, they go by last menstrual period.