Clover,

At our 20-week scan, I knew we were spot-on 20 weeks because we conceived through IVF - you can't fake those dates! But the sonogram said that Bub was measuring somewhere between 18 weeks and 19 weeks. I asked the MW later if that meant anything, and she said it means NOTHING but that the sonographers have to have some sort of point of reference to go by, and obviously all babies have to fit into a "scale" - which means some will measure "behind" and others will measure "ahead."

I had a scan at 36 weeks the other day (as part of any ECV) and the sonogram was measuring Bub's head at 37 weeks, and his femur at 35 weeks 1 day. Again, we were told this means NOTHING because what they're really concerned about is whether he measures within "normal" dates for the "average" baby.

FWIW, my Mum knew her dates when she was pregnant with my sister, and was told that baby was "small for dates" and that they would induce her on her EDD because my sister was "sick" (they also said that it was because my Mum was a vegetarian ) My Mum went into spontaneous labour on the EDD, and my sister was 6lbs 9ounces - not large by any standards, but right on "normal" for a healthy baby.

GL - and congratulations on your little girl!