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Pregnancy

Talk about every stage of pregnancy, from early symptoms to preparing for birth.

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Original poster

How accurate are growth scans?

15 replies

iloveholidays · 22/02/2011 10:57

I just wondered whether anyone had any experience in how accurate they've found growth scans?

I had one a week ago estimating the baby at 3lb 4oz. I've seen my midwife this morning (now 34weeks) and she said that she can't believe there the baby is only a 3lb-er in there!! My midwife is very experienced and I have a lot of trust in her, but also don't want to get my hopes up, as I'm currently being monitored twice a week and on the consultant list due to lack of growth.

Now completely confused!!!

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Nagoo · 22/02/2011 11:34

IME not very accurate at all... suspected low weight turned out to be a 9lb baby. How can this be?

Fantail · 22/02/2011 12:05

The doctor told me yesterday that they can be around 20% out.

fizzyliftinggas · 22/02/2011 12:08

I disagree entirely with my 12 week dating scan, as is physically impossible that I got pregnant 10 days later than I thought due to when I got +ve test result.
The fact I am carrying twins would throw out the measurements slightly IMO.
But that's not a growth scan obv so I'm not 100% sure, but I wouldn't get too hung up on the results

asdx2 · 22/02/2011 12:09

Dsis had a scan the day before her babe was born where they estimated babe was about 5lb. Dn was born less than 24 hours later weighing 9lb 12oz.

TittyBojangles · 22/02/2011 12:10

Growth scans aren't very accurate. They give a sort of overview of the baby and may highlight issues with the fluid levels etc. But don't get too worried about the weight calculation itself.

TittyBojangles · 22/02/2011 12:12

Also, you are only 34 weeks so there is a LOT of growing time left! :)

Scruffyhound · 22/02/2011 13:12

Im having a scan on Thursday will be interesting..... The growth charts I think are way out! I was told 11lb he was only 8lb! Not sure how the scan works not had one this late before! Would not worry too much I think a lot of it is rough estimation.

Annpan88 · 22/02/2011 13:22

oh no I was hoping they where accurate as they said my water levels were on the lower end of normal and everything was fine, but I am very tiny at 38+2 weeks. 34cm on sat:( now I'm worried the scan was out

Original poster

iloveholidays · 22/02/2011 14:31

Well its encouraging to know that the baby could be bigger than estimated.

I've been put on the consultant list because there was no growth in the abdominal over a two week period rather than the actual size, but obviously the bigger the baby the safer it will be when its born.

My DD arrived at 36+2 so might not actually have that much longer. Also, if there is no growth shown in the next scan in a week then I think I maybe induced or booked for a section as baby currently breech.

In the meantime I'll keep eating lots in the hope it helps!! :)

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TreeHuggerMum1 · 22/02/2011 14:44

They are way out - my little one at 32 weeks was apparently just under 5 lb and nearly two weeks later he was born in between 34 & 35 weeks he weighed 3 lb 14 oz...
Take it with a pinch of salt.

mejon · 22/02/2011 14:48

DD2 was estimated to be 6lb 9oz at 36 weeks and my MW was most concerned that I shouldn't go overdue and risk having an enormous baby. She appeared after induction 12 days overdue at a 'whopping' 7lb 2oz so I'd say the scan was way out! Had she been 'on time', she'd have probably been even smaller than DD1 who was 6lb 10oz at birth.

midori1999 · 22/02/2011 16:11

I was reading something yesterday that said they can be out by around 10%, but the more measurements they take can reduce it by 5% margin of error.

I had a growth scan at 39 weeks in my first pregnancy, which estimated baby would be about 9lb at birth. My midwife refused to believe it, saying there was no way I'd have a 9lb baby, these scans were always wrong and baby would be 7lb maximum. DS was born in the early hours of the morning after his due date weighing 9lbs exactly.

Scans with DS2 and DTD's were very accurate too. DS2 esitmated to be 9lb at 36 weeks, had him at 38 weeks weighing 10lbs. DTD's were estimated to be 1lb 2oz and 1lb 4oz the day before birth (at 23+5) and were each born weighing exactly that!

hollandbaby · 23/02/2011 10:12

I went for a scan yesterday, at 34 weeks and 5 days. The last scan was at 27 weeks and the abdominal was in the 95th percentile so the midwife wanted to check the size. When we went yesterday the scan showed the abdominal as going down to the 65th percentile but the head width (which was above average percentile) showed small on the 5th percentile, this worried us so much. when we spoke to the midwife she said that the scans for the head cant be accurate especially becuase the baby is head down in the pelvic area and not to worry as the change couldnt have happened at this stage. I still feel so worried that my midwife is just trying to make us feel better. Do you think the head width scans can be that inaccurate? ive been feeling so happy and i dont want the last 5 weeks or so of being pregnant to be such an anxious time. thanks for any advice.

Original poster

iloveholidays · 23/02/2011 14:04

Hi Hollandbaby. I can't really speak from experience, but what your midwife is saying seems logical to me.

I can also say that if they were worried they'd be monitoring you more thoroughly... believe me!! I had no growth over a two week period on the Abdominal and I'm now being monitored a lot. Apparently that is the area they are most concerned about at this stage as the baby should be putting on fat.

My baby is breech so not had any issues with measuring the head.

I would keep positive... I honestly believe if there was something to worry about you'd be the first to know.

Good luck with the rest of your pregnancy!

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tlise · 23/02/2011 16:29

It depends on how accurate they measure and imo they all measure slightly differently. I was told my youngest DS was going to be a good size, if he had been at 40 weeks would have only been 8lb. I don't think he was that big lol.

Mw can be wrong as well though. It was a stand in that had me sent for a growth scan in the first place, she said she thought he was over 9lb at 36 weeks...

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