Ultrasound Accuracy (Fetal Weight)

Discussion in 'Pregnancy - Third Trimester' started by 2nd Time Mom, May 31, 2011.

  1. 2nd Time Mom

    2nd Time Mom Well-Known Member

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    I had a scan last Thursday that put me two days ahead... Due date did not change from Aug 21tst due to the small difference in days.

    Anywhooo... The sonographer said the baby weighed 2lb 9oz....

    How accurate is measuring fetal weight via ultrasound????

    Just wondering. Thanks!
     
  2. cbmd

    cbmd one little boy - milo

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    i got told the later on scans go the less unreliable/accurate they become, i have had to have a few extra scans during 20th week and one in 35th week, midwife told me they can be as much as 25% out either way later on.
    x
     
  3. abc123x

    abc123x Well-Known Member

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    My baby measures over a week ahead, and I've already been put forward a week, so they usually don't move you if it's just a few days.

    I understand that the weight on US is a decent estimate, yet not 100% and the weight your doctor would guess based on your size is very inaccurate.
     
  4. Cupkake.Luver

    Cupkake.Luver Mommy to my Babbacakes!

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    I can let you know tomorrow! I have a doc appt. Had an ultrasound (growth, amniotic fluids...etc) last Thursday and get to discuss results at the docs tomorrow.
     
  5. 2nd Time Mom

    2nd Time Mom Well-Known Member

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    Thanks Everyone...

    I always am a little skeptical about ultrasound accuracy when they get into weight... Limb & head size I can understand, but weight I just get a little iffy...

    With my first born, I was originally set a due date of May 12th.. After 20 week scan they moved my due date to May 1... Saying he was huge. But I was induced and he was born May 3rd only 6lbs & 12 oz.... Not a huge baby at all!

    lol!
     
  6. 2nd Time Mom

    2nd Time Mom Well-Known Member

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    Perfect. Thanks! I will wait to hear back.:thumbup:
     
  7. tjw

    tjw Mum to Ruby and Preggers

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    It was spot on for my lil girl, I was scanned at 36+0 and was told she was about 8lbs. 2 days later I had her by emergency section and she was 8lbs 3oz.

    This time I am currently 28+2 and my boy is already at 3lbs 7oz, so he's a few ounces ahead of his sister at this point (she was 3lbs4oz at 28+1) but not by much. He is measuring 3wks ahead, so I expect my due date to get changed when I go see obstetrician on Friday.
     
  8. maddog37

    maddog37 Well-Known Member

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    The common believe is that they could be 1 lb off both ways, but I'm pretty sure it could be off more than that.

    Even regarding length measurements, it could be off. I was told that I'd have a short baby as his femur was in the low percentile, and was told such comforting words as, "well, don't worry, it's not like it's a midget baby". And what happened? LO came out taller than average.

    All his development measurements put him a week or so behind my EDD. He came out the day before my EDD with cracked dry skin on his feet and hands. The pediatrician said it's due to baby being overdue. So who knows!
     
  9. eeyore123

    eeyore123 Pregnant with baby NO 5

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    they are not always right........... in fact some times they are far off........ i carry small (long bodied so baby hides well ) so end up having growth scans later on in pregnancy........
    with my 2nd i went for growth scan on the tuesday, they told me she was close to 9lb.......... on the thursday morning i gave birth to a beautifully average 7lb 5 oz baby.
    with my 3rd they told me he was in line with my other 2.. ( both 7lbers) he was born 5lb 15oz......
     
  10. lynys

    lynys Charley's Mommy

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    Mine was WAY off. Charley measured two days before delivered at 6 1/2 lbs. She was born 5lbs 12oz.
     
  11. 2nd Time Mom

    2nd Time Mom Well-Known Member

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    Thanks again everyone!
     

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