J.B.
Well late term sonograms are notoriously inaccurate. Usually the early ones are much more accurate, so whatever due date you got at your original sono, is probably right. Tiny baby's don't have fat etc and are all pretty much a standard size in early development so the due date can be considered correct. Later on babies vary so much more so predicting the date is so difficult. My babies always show that I am much farther than I am in late term ultra sounds, like 2 or 3 weeks. Did you give them the first day of your last period and have an early ultra sound? That should have been pretty good as far as accuracy goes. Good luck, sounds like a tough situation, hang in there!!