OMG, really.. How many times are you gonna ask??? No the U/S can't tell the difference between the blood and many women don't have implantation bleeding or didn't know thats what it was..
The ultrasound measures the baby.. From that plus your LMP they give you an estimated due date... It is estimated and that date can change a few times during the pregnancy..
at 1:29 AM on May. 26, 2011