I would not worry yourself too much. I was told at my 20 week scan that my DD was 2 weeks behind in growth and that I would need to be monitered to ensure she was growing ok, I had another scan at 26 weeks and she was still 2 weeks behind. I went in for a scan at 28 weeks and was told that my baby was so small that it would not survive unless I delived her that day. I demanded another scan as although my belly was small I did not believe them, they kept me in all day and at the end of the day I had another scan and was told my baby was in the 'normal' size range for my date , so they could have delivered my baby that day for absolutly no reason and risked her life. I was told DD would be a 5 - 5.5 pound baby at 40 weeks, she was delivered 6.6 pounds or 2987 grams at 38.2 weeks.

Next time around I personally will not be getting sizing scan.

Don't stress about it too much, the further along in pregnancy you are the less accurate the scan is for measurements, the earliest scan is the most honest in size/date.

Deanne.