How accurate are baby measurements when pregnant?

[NotLongToGoooo]

I'm 38+3.
I'm due to have a c section next week.
Baby has always measured bigger but just within normal range.
They've done another scan today and have said she's on the 99th percentile (8lbs 4). Therefore tipped slightly over the 'normal' range.

I'm wondering how accurate the measurements actually are as I've heard different stories from people who have said their baby was a completely different weight to what was predicted from scan measurements etc.

They're saying they feel it's safe to wait until the c section date next week as I will be a few days over 39 weeks by then, and they prefer to wait until after 39 weeks so their lungs are fully developed.

Not at all. I was told 7lb10 at 39 weeks, born a week later at 6lb3

Huge margins of error for them. A scan is more accurate but still has a margin.

IME newborn clothes still fit them for a week or two so def worth taking to hospital. 0-3+ is the one you want the nicer things in though, if you have the opportunity to exchange things. But it is nice to keep one of the teeny tiny outfits as a keepsake :)

They thought DS was small. Bump measured behind but scan at 36 weeks showed 7lbs 1 and he was born 40+3 at 8lbs 2

Mine were spot on, including the one I had 12 hours before she was born (predicted 3.74kg and she was 3.71kg).

I don’t think they’re really that accurate but definitely a lot more accurate than when they measure your bump. My little boy was calculated to be 7lb 6 or 7 at birth but ended up being 8lb 5!

Scan at 32 weeks estimated baby at 5.5lbs and likely to be 9 or 10lbs at term. Born at 39+0 weighing 6lbs 13.5oz. Second child I didn’t have a scan but they estimated from palpating and fundal height it would be a small one. 8lbs 12.5oz that time.

I had a scan where they estimated 8lb 13, baby born 3 days later at 9lb 13.
Other baby pretty much bang on though

My mum was told I would be tiny, about 4lb, they had the paeds drs on call when I was born and I was 7lb 9. Same for my sibling, told they would be tiny and ended up being over 9lb.

First had I had growth scans. 36 week scan was 6lb 15, popped out 7lb 5 a week later. So pretty bang on.

Second was no growth scans, but my trust have a 36 week scan as standard. Was just a little bit off. Scan said 6lb 12, 2 weeks later baby came out 8lb 1. Little bit off (baby was bigger than scan estimate), but pretty close.

Jeepers @Dilbertian I'm glad you clarified that.
You gave me a fright - between 9 and 19lbs !!!!!!! 😂

At 42 weeks pregnant I was told I was having an ‘average sized’ baby. Out popped 10lb DS.

Scans were very accurate for me. DS1 was 50th roughly and DS2 was 25th centile roughly. That was what I got. Bump measurements were always inaccurate for me. I did carry small so I always measured small. No concerns at the growth scans though, just how I carried.

Based on fundal height measurement as opposed to a scan, but I was told two weeks before I was due that my baby would likely be 9lb+.

She was born at 40+5 and was 7lb8oz.

@NotLongToGoooo How come they want to bring it forward if you’re having a C Sec though? Big baby is just a big baby if no other risk factors?

I was lead to believe that she’d be 9-9 1/2 lbs and everyone was being very dramatic and stressing me out about it. She was born at 11lb 7. No way I could have gotten her in newborn stuff!

UPDATE:

Hi All!
I wanted to post an update -
I went into labour 4 days after my post ... baby weighed 7lbs 10 so was a little under what was predicted.

NotLongToGoooo congratulations!!

Congratulations! …. And proof they usually get it wrong 🤣🤣

Both times my bump measured bang on 50th centile but my hospital was taking part in a study so we all got scans at 36 weeks.

DC1 they said was smallish and estimated <7lbs at 40 weeks. He was 8lb 12 (75th centile)

DC2 they said was big and estimated 9lb at 40 weeks. She was 9lb exactly on her due date (91st centile).

So for me 1 scan was accurate, 1 inaccurate, but bump measurement totally wrong both times!