Post # 1
For those of you who have had babies, what was your experience on growth scans in the third trimester predicting birth weight? Everything I read is that the margin of error is pretty big, but I’m interested to know if this error tends to swing one direction or the other in terms of over vs under-estimation.
So if you had a growth scan in the final weeks of pregnancy, did the growth scan over or underestimate your baby’s birth weight?
(Allowed multiple choice for those with multiple kids where the accuracy may have varied a lot between kids!)
Post # 2
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
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
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
- 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
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
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
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
- 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
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
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
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
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
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
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!