Your doctor will go by whatever date they set last. Remember, it's an ESTIMATED due date, and unless you or the baby is unhealthy, there really is no such thing as 'overdue'. But since doctors like to rush nature, they will likely say you are 'overdue' June 21. My advice, stay pregnant until that baby wants to come out (or if you or it gets sick of course)

I told my doctor PLENTY of times I gave them the wrong date of my LMP (it was the 9th, I told them 17th) and they still went with what I told them first. If they would have listened to me, I would have had my baby a week sooner. They induced me, but wanted to wait until I was 38wks. So I was actually 39wks when I delivered. They even confirmed it by saying she looked like a 39wker.

So, that being said... how do they calculate what week you are? Since the last due date they gave me was the 20th, am I 39 weeks or 40?

Due dates are estimates. The earlier ultrasounds will give better dating, since as a pregnancy progresses babies grow at different rates.

That said, an estimated due date is or - up to two weeks. No one can predict when the baby will come with a lot of accuracy. That is why some women just say, "The end of June." and don't focus on a specific date. Most first time pregnancies go over their EDD. A lot of people are upset by this when it happens. Focus on having a healthy child and not a date. Women do not remain pregnant forever. The end always comes. But the end is really up to the baby.

You are 39 weeks if your due date is the 20th. You will be 40 weeks ON the 20th.

Thanks. I know that it's just an estimate. This is not my first child. But my doctor explained things better last time. Now, when people ask when I'm due I don't know what to say! lol. I just say "soon" or "any day now". This is all new since I was induced my last pregnancy at 37 1/2 weeks because of PIH and I ended up having a c-section because I wasn't "ripe". But thanks again for the quick replies!