Later ultrasounds are not accurate in determining due date. Growth rates of babies varies in the womb in the later stages of pregnancy.

Go with the later due date, that way if baby comes 'earlier' you will be pleasantly surprised. If you start using the earlier due date, you'll be sorely disappointed (going overdue can be devastating!) if baby is 'late'.

Why would your doctor insist on keeping the due date? He is the doctor.

The further along your pregnancy is, the harder it is to pinpoint what your expected due date would be. If your doctor came up with sept. 2nd early in your pregnancy, that's probably more accurate. It's possible that your baby is just measuring larger than they had expected. I would trust your doctor. Besides, if your baby surprises you a week or two early, wouldn't that be a good thing? Instead of expecting him/her on august 19th and having that day pass with no baby?

Yes she is my doctor. And thank you for your response.