Those with kids – Growth scans vs birth weight (Poll)

posted 1 month ago in Babies
  • poll: Did your late 3rd trimester growth scan over- or under-estimate baby's birth weight?
    Significantly over-estimated : (5 votes)
    9 %
    Somewhat over-estimated : (10 votes)
    19 %
    Fairly accurate : (21 votes)
    40 %
    Somewhat under-estimated : (11 votes)
    21 %
    Significantly under-estimated : (6 votes)
    11 %
  • Post # 2
    491 posts
    Helper bee

    Hmm.. I was measuring on point and told my baby was around 6-7lbs. I had over an 8 lbs baby, close to 8.5 lbs. my OB told me they are usually off. Also, I gained the recommended 30 lbs and I’m a healthy weight. No issues and healthy pregnancy too. Just had a big baby. 

    Post # 3
    125 posts
    Blushing bee
    • Wedding: November 2020

    Typically we can be off 1lb in either direction late in pregnancy. Your tech will likely have an idea if the estimated birth weight is a good estimate or is over/under based on how good the images they were able to get were (can get very hard towards end of pregnancy). I’m interested to see what everyone says! 

    Post # 4
    1421 posts
    Bumble bee
    • Wedding: February 2011

    One of my babies was accurate and another was over-estimated by a pound. Generally speaking, macrosomia isn’t a reason to intervene unless there are co-morbidities or risks so relying on late-term growth scans isn’t ideal.

    Post # 5
    701 posts
    Busy bee
    • Wedding: June 2007 - City, State

    TravelingBride31 :  my last scan before my 4th baby was born put her at 7lbs 5 oz. This was 4 days before my scheduled csection. She was exactly 7.5 at birth.

    Post # 6
    443 posts
    Helper bee

    I’m not voting because we didn’t do any growth scans, just the typical 20 week anatomy scan.

    However, all the birth stories I’ve read (and I read a lot over those 9 months! 😆) reported that the baby measured large then was born 2-3 lbs smaller than predicted. Of course, that’s all anecdotal and people are more likely to write about situations where the doctors were off. I’m interested to see the results of this poll!

    Post # 7
    518 posts
    Busy bee

    I don’t remember exactly, but baby was measuring a little on the small side at my 32 week scan, and my fundal height measurements also were a little on the small side throughout the 3rd tri. Baby came out smallish at 6 lb on the dot. 

    Post # 8
    563 posts
    Busy bee
    • Wedding: August 2014

    At 38 weeks, they estimated current weight was 7lb3oz, he was born a week later at 6lb13oz. So not too far off. But I definitely have friends who have been told they should expect a 10lb baby and ended up fairly average at 7.5-8, and one who went the other way expecting an average baby that was on the big side. 

    Post # 9
    226 posts
    Helper bee
    • Wedding: June 2019 - Sandpoint, ID

    bethio :  Same in that we only had the 20 week anatomy scan.  I was thinking our son would be bigger than he was based on how big my mom’s and husbands mother’s babies were. Our son was a peanut at 6 pounds 4 ounces and 19 inches long. Normal pregnancy and healthy baby at full term. 

    Post # 10
    541 posts
    Busy bee
    • Wedding: June 2017

    All of the scans I had in the third trimester were around or before 36 weeks and my three were delivered at 39, 39, and 37 weeks respectively.  I personally measured big (at least 2-3 weeks ahead), and there was concern with my first that I’d have a huge baby. They were 6.11, 7.11, and 7.1. So clearly, none of the measurements were exactly accurate. All of our kids were over 5 pounds at the time they were measured, but none ended up as large as the OB had predicted. 

    Post # 11
    6560 posts
    Bee Keeper
    • Wedding: February 1997

    They were fairly accurate with my first two, both around 9-1/2 lb. With my last, they said they refused to estimate with babies over 10 lb, and she turned out to be 11 lb 7 oz. Both because of size and because of a transverse lie and polyhydramnios, she was born c-section (for which I was grateful!).

    Post # 12
    140 posts
    Blushing bee
    • Wedding: May 2017

    At my “overdue” appointment at 40w2d, the ultrasound estimated my daughter to be 6lb 12oz and she was born the next day weighing 6lb 10oz!

    Post # 13
    1111 posts
    Bumble bee
    • Wedding: September 2017

    I had one at 36 weeks and he was estimated to be 6lbs 6oz at that time. He was born at 40w3d and was 5lbs 15oz. 

    Post # 14
    3225 posts
    Sugar bee
    • Wedding: May 2015

    I don’t remember specifics of the growth scans but I was told that both of my babies were “small babies”. Both of them were born at the top of the charts height wise and slightly above average weight wise. First was 8 lbs 8 oz, 24″ long at birth and the second was 8 lbs 6 oz, 22″ long. 

    Post # 15
    434 posts
    Helper bee
    • Wedding: September 2015

    My OB’s office doesn’t do growth scans until 40 weeks, but my doc estimated based on feel. For babe #1 she said about 7 lbs, and she was 7 lbs even! For the second, she guessed a few weeks earlier and thought she’d end up closer to 8 lbs, and baby was 7 lbs 5 oz. So not bad!

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