How accurate is the early pregnancy scan dating? The dating is most accurate when the scan is performed between 7-11 weeks. The Estimated Date of Delivery (EDD) is accurate to within 3 days and is calculated from measuring the length of the embryo (Crown Rump Length).

Can you see a baby on ultrasound at 7 weeks?

At seven weeks pregnant, your baby is about the size of a blueberry! Now you can figure out your due date, and use an ultrasound to detect the babys heartbeat and brain development.