Because she usedmy second u/s dates (at 19wks) rather than the first dating scan (at 8 and a bit wks) to estimate. I will talk to my gp about that. I tried to tell her I had another scan before that, but she wasn't listening. I'm not worried about my due date really. I don't know exactly when my last period was so I don't know exactly when bubs is supposed to be due. But I'd say in mid to late August just on my gut feelings.