At around 12 weeks you can get more accurate measurements. You need to be logged in to do this Of course you have probably already used an online due date calculator. It's because it gives a definite date for health professionals to work with. My baby will come when it's ready anyway, maybe weeks before or maybe weeks after my due date.
I have scans every few weeks so it will probably keep on changing.
Can your pregnancy scan give the wrong due date?
But then again with my first baby I was spot on with dates, he always measured big and he was a week overdue At around 12 weeks you can get more accurate measurements. In the UK, most pregnant women don't have an ultrasound until they are at least 12 weeks pregnant. Well, you'd think so, wouldn't you. Unless you have an early pregnancy scan most of you will be given your estimated due date at the week scan. Perhaps you are based in the US, or another country, where ultrasound practice is a bit different? The sonographer then said that I was only about 4.