How accurate is estimated birth weight?

[Londongirl84]

At a scan we had today (35 weeks) they estimated our baby to weigh 8-8.5lbs on her due date. How accurate is this??

[Ratbagcatbag]

Not great. So don't panic!!! At 33 weeks, I was told baby was already 7-8lbs. It certainly made the sweepstake interesting. (12lb guesses ) dd was born 37+4 at a ok 6lb12oz.

[Londongirl84]

They estimated she already weighs 5lbs 9oz which seems big for 35 weeks!! Glad you say they were wrong for you ratbag x

[Northumberlandlass]

Not great. Estimated 8lb on due date, arrived a little late at 10.4lb

[WitchOfEndor]

Not. DS was supposed to be 10lbs and he was only 7lb 4oz (thank goodness)

[Piggytastic]

Ds1 estimated 6lb and was 8.5, ds2 estimated 9lb+ and was 8.3
Not accurate at all!

[AnitaBlake]

They estimated DD1 as 5lb at 34w, she was 4lb 11oz when born at 38w.

[ISpyPlumPie]

DS1 was estimated as 6lb but was 9lb 2oz. O know this is an error in the opposite direction to reassuring but
a) it was based on prodding by a mw rather than a scan
b) he was almost two weeks late.

With DS2, I'd worked out he'd be a 10lber based in his scan weight at 30 weeks allowing for 1/2lb per week gain until birth. He was actually 7lb 10oz.

Everything I've heard suggests estimating birth weights is a rough science at best.

[BrokenBananaTantrum]

DD was estimated to be 8lbs at 38 weeks. She was 5lb 12oz at 40 weeks so ime not accurate at all!

[DipDabDabDip]

I got told "well she's not going to be a small baby" at 32ish weeks. Dd came out 11 days overdue at a tiny 6lb 15oz.

I don't think they're very accurate at all.

[Pommes]

Not accurate at all. Was made to feel quite worried I had a very big baby, delivered at 39 weeks a 8lb 4oz DS.

[Londongirl84]

This is reassuring! I don't want a big baby!

[Pinkbell123]

I'm 35 weeks and today was told mines already 7lbs 8 so I hope its a bit out! Rescan in 2 weeks time so will see what that one says.

[3bunnies]

ds was estimated at 8lb, greedy guzzler got an extra 12oz out of me by the time he was born 30hrs later or maybe the scan was a tiny bit inaccurate

[KateH32]

Not accurate. Was told 8lbs - got 10lbs 3oz!

[FrequentFlyerRandomDent]

It is not very accurate. It is a calculation based on diameter of thorax if I remember correctly. There is an average 400 gr error margin either side of the prediction.

[FrumiousBandersnatch]

They underestimated in my case. Estimated birth weight of approx 7lb from 32 week scan, every hcp involved in birth examined me and told me baby was not big, DD born with assistance and weighed 9lb.

[GlitzAndGiggles]

DD was estimated 6.9lbs and born 7.7lbs

[sittingagain]

At 36 weeks plus 5, at 11am, ds2's weight was estimated to be 8lb.

He was born 14 hours later, weighing 7lb 4oz.

[RandomMess]

They kept telling me I measured small for dates, and the baby wasn't big (even though I'm a short arse and looked huge) she weighed 10lb 6oz...

[Inkspellme]

scan estimated 7lbs. dd arrived 10lb 8oz.

funnily, she was breech and the doc who was going to try to turn her said by feel she was closer to 10lb. That was the same day as the scan. He didn't turn her as she was too big to move. I'm five foot 1" in height.

[Ilovekittyelise]

i had various growth scans in last pregnancy and estmates themselves varied by about 2 pounds. seems even dodgier than the tape measure!

[AnythingNotEverything]

There's no need to fear a big baby. Most newborns have heads of a very similar size, and it's the head and shoulders that are tricky to pass. They can be really long or fat, and it doesn't make any difference.

However, it is thought that big babies have more help from gravity.

Big babies get stuck just as often as small babies - positioning is much more important than size.

Also, big babies are much easier to handle. You're less scared of breaking them manipulating their arms into babygrows as they're stronger.

[LottyLikesWindows]

I would take it with a pinch of salt. At 34 week scan we were told that DD would weigh 8lb. She was in fact 9lb3oz so not even close.

Last week I met a poor woman who was also told to expect an 8lb baby too but ended up delivering a huge 12lb9oz baby.

[LottyLikesWindows]

Oh and I second anything's post - my little strong chunky monkey is very easy to dress. No faffing about worrying I'll break her tiny arms. She's very strong!

[Karen1226]

I had a growth scan at 34 weeks and estimated 5lb 11oz and my midwife assures me this will not be a big baby. However we rarely have babies under 9lb in my family and if she is small I have no excuse for putting on nearly 4st!