"Estimated" weight of bub via Ultrasound.. accurate?

**Ashi** · 24-12-2008 08:26

So ive been wondering ... just how accurate are their weight "estimations" from ultrasounds done in late pregnancy...

at 32 weeks my bub was just under average at about 1.3 kilos i asked if this was bad they said no shes just a small bub..

then at 36 weeks they told me she was a "big bub" and looked about 3 kilos already ...

does that sound odd to anyone!??! lol

the OB told me he thought she would be about 9 lbs when she was born...

strange thing is that she will be "if she is indeed that big" my biggest baby..

with my others being 8lb 7(was overdue) then 7lb 1 then 7 lb 3

and the diffrence between this bub and my other kids is a much smaller built father...

dosent make sence to me...

could they be off on their esitmates..?

has anyone experienced being told to expect a BIG baby as a result of a late pregnancy U/S (not just guessing because of fundal height or belly size..)

and actually had a normal size baby??

TIA

**84zsazsa** · 24-12-2008 08:34

This one is sooooo funny to me because while preggers with my boy I had to have a scan at 32wks. At that scan he was measuring 1lb heavier then he should have been and I was told as a given that he would be 10lb plus....possibly even 12lb like his father was at birth!!!!!....

He came out weighing....wait for it ....7lb 9oz....

Way off!!!!

Danni

**Deserama** · 24-12-2008 08:55

No they are very rarely accurate at all! I don't know why they even bother.

**Tam-I-Am** · 24-12-2008 08:55

Ultrasound is notoriously inaccurate at judging the weight (and indeed, size) of the baby and measurements should be taken with a grain of salt. There are many many many documented cases of women being told their baby would be MASSIVE or tiny - and was quite a normal, healthy weight. I get quite wary when Obs tell their patients that they *need* a c-sect or induction on the basis of US weight....There's no call for it.

**mum_I'm_hungry** · 24-12-2008 09:02

My first was 50 grams out (I had a late scan at 37 weeks) and my second was 300 grams out (obstetrician's guess). So pretty accurate here!

**MacAidan** · 24-12-2008 09:12

I had the same obstertrician for all three pregnancies, and each time I asked him "is this baby going to be big" and each time, he said "we'll know when it's out"

He seems to think that you can't tell accurately how big bub will be until they are born.

**flick82** · 24-12-2008 09:18

I was told at 30wk scan I was going to have a big baby over 9pd, I was induced at 37wks and she was 3.53kgs so it was pretty accurate for me.

**bel_aiden** · 24-12-2008 09:19

http://www.amnionet.com/p188.htm

this has a little table that has approx weight % at different weeks of gestation. if your 36 weeks and bubs is 3kg, it says bubs will be approx 3.78kg (8lb 5oz) at 40 weeks

**Herchy** · 24-12-2008 09:49

pfftt I was also told a baby in excess of 11 pounds..... He was a touch off 9 pounds, which to be honest, I don't think is that big at all.

The later in pregnancy the scan, the less accurate.

**Ashi** · 24-12-2008 14:55

Originally Posted by 84zsazsa

This one is sooooo funny to me because while preggers with my boy I had to have a scan at 32wks. At that scan he was measuring 1lb heavier then he should have been and I was told as a given that he would be 10lb plus....possibly even 12lb like his father was at birth!!!!!....

He came out weighing....wait for it ....7lb 9oz....

Way off!!!!

Danni

I hope thats the same for me! lol

i dont care what she weighs of course i just want her to be healthy...

but id prefer not to push out a massive baby.. or end up having another c sect

!