Growth Scan Accuracy?

[hillary8l8]

When I had my daughter, I didn't keep very good track of her growth scans. I know she measured small, but I never really listened to how much they predicted she weighed. I know at 35 weeks, she measured 33, and that's about all I can remember. This time around I have had growth scans every 4 weeks to keep track of the size to watch for IUGR since my daughter was so small. Well, I had my 35 week appointment with a growth scan this past Tuesday, and they predicted his weight at 6 lbs 8 oz. The potential for this to be such a big baby kind of scares me considering my daughter was only 5 lbs 0.5 oz. In 4 weeks he went from a predicted weight of 3 lbs 14 oz to the current predicted weight of 6 lbs 8 oz, so it seems that he is growing very well. I just can't stop thinking about the fact that I could potentially be giving birth to a 9+ lb baby. I was just wondering if anyone has any experience with the accuracy of the predicted weight on these growth scans?

[angieb]

The margin of error gets larger the bigger the baby gets. I remember when DS was measuring around 10 ounces, the margin of error was like an ounce. When DS was measuring 5 lbs, the margin of error was a pound or maybe 2. (The tech always told me the margin of error that the computer calculated along with the pounds and ounces.) That being said, with both of my kids so far, the ultrasounds were really close. Olivia was estimated to be 12 oz (and that tech was being overly generous I think under the circumstances), she was 10.5, Lucas was measuring about 5 lbs (I think) at 34 weeks, he weighed about what we expected...7 lbs 4 oz at 36+2.

[marilyn621]

My daughter was measuring too small but her doctor told me she should come out to.be about 6.5-7 lbs. Well surprise! She was 8lbs 2oz! The ultrasound predicted this one at 3lbs 1oz at 29 weeks (that seems big to me?) but I don't really trust it after last time.