How accurate were your 3rd trimester scans/measurements?

[Jcmummy32]

Hi everyone

First time pregger here and I’m so anxious. Had a scan at 31 weeks with some of baby’s measurements high and weight estimated to be 1lb ahead. Did any of you have this experience and if so, how did it compare to baby once they arrived?

Does measuring ahead mean DD could be off?

Hello. I don’t think measuring ahead at that stage bears any relation to due date - after 20 weeks ish they grow at such different rates anyway.

The scans are only accurate to 20% either way, which can be a difference of 1-2lbs! I had similar recently when my 35 week scan suggested baby was very big, and I had loads of people telling me about their scans being completely out. Actually though, she was born last week and was pretty much exactly what the scan estimated she’d be!

There is so much margin for error. I was measuring 2 weeks ahead and at my 36 week scan they estimated baby was on the 85th centile. I was inducted due to this. Baby was born at 40+4 weighing a healthy 7lbs 6ozs, so not tiny but definitely not a huge baby! I definitely wouldn't worry too much as more often than not they get it wrong.