Please remind me that u/s is not super accurate

mystrana · August 2012

Two weeks ago my OB thought the baby was measuring small so we got an u/s done Friday. The tech took the measurements and most of them were slightly above average (like a week) in her estimate so she concluded that the baby was growing fine.

But, baby is head down at this point and I guess that made it hard to get a good picture to measure for the head measurement? Every time she started drawing the line to measure the head, I could see the u/s screen showing that the head was supposedly measuring almost 4.5 weeks ahead.

I know that nature matches me up with a baby that it designed to be birthed by me, but I am freaking out just a touch nonetheless. Please share your stories of u/s measurements being off, or, I guess, techniques for me to stop looking at DH's baby pictures and freaking out about how big his head was(/is)!

CTri17 · August 2012

Honestly, I wouldn't worry about it, at this point just keep cooking this baby and preparing

mystrana · August 2012

CTri17:
Honestly, I wouldn't worry about it, at this point just keep cooking this baby and preparing

I appreciate it! It's silly, but I am sometimes a worrier.

hilwithonelary · August 2012

I have a friend who just gave birth this week. She had GD, so she had several growth scans. At 36 weeks, they said the baby was 8.5 pounds. At 38 weeks, they estimated 9.5 pounds. The baby was born on Tuesday just shy of 39 weeks. 8 pounds even

Thankfully, she narrowly avoid her scheduled c section for suspected macrosomia.

ReichleyMama · August 2012

With my first I always measured WEEKS behind. My OB yelled at me constantly. I was underweight before getting pregnant and only gained 20 lbs. I was sent for numerous extra ultrasounds. I knew my baby was fine because I was eating healthy and normal. Just a week before I delivered I was told the baby would be less than 5 lbs. Abigail arrived on time weighing in at 7 lbs. 8 oz. Perfect!

Same month that I delivered my cousin was induced a week before her due date b/c she was measuring so large and u/s showed 10 lb baby. Delivered by c-section, baby Justin weiged in at 6 lb 11 oz.

They don't know.

mystrana · August 2012

ReichleyMama:
With my first I always measured WEEKS behind. My OB yelled at me constantly. I was underweight before getting pregnant and only gained 20 lbs. I was sent for numerous extra ultrasounds. I knew my baby was fine because I was eating healthy and normal. Just a week before I delivered I was told the baby would be less than 5 lbs. Abigail arrived on time weighing in at 7 lbs. 8 oz. Perfect!

Same month that I delivered my cousin was induced a week before her due date b/c she was measuring so large and u/s showed 10 lb baby. Delivered by c-section, baby Justin weiged in at 6 lb 11 oz.

They don't know.

Those kind of stories are exactly what I was thinking about before the u/s and the during it, it was just so hard not to be caught up in the "this is science and based on a lot of measurements" aspect of it. Thank you for sharing.

nosoup4u · August 2012

I gave birth to a giant baby (10 lb 10 oz, 14.5" head), and tore, but I barely remember the crowning portion of my labor. By the time they come out, it's over! You'll do great - as cheesy as it sounds, visualize yourself pushing that baby out, I think there's a lot of "mind over matter" when it comes to med-free. Good luck!

Birdies08 · August 2012

nosoup4u:
I gave birth to a giant baby (10 lb 10 oz, 14.5" head), and tore, but I barely remember the crowning portion of my labor. By the time they come out, it's over! You'll do great - as cheesy as it sounds, visualize yourself pushing that baby out, I think there's a lot of "mind over matter" when it comes to med-free. Good luck!

My baby also had a 14.5" head and I didn't feel a "ring of fire" or anything when she crowned. I did tear, but my MW swears it was only because she had her hand up by her face. I didn't know that I tore until she told me, either.

I know those u/s aren't 100% accurate and would not worry about how many weeks ahead it says you're measuring. The most important information you got from it is that the baby is doing well

MangomamaFL · August 2012

With my third with an U/S done at around 22 weeks LMP:

-He measured 5 week older than EDD based on LMP

-I had quickening 3 three week earlier than I had with his two older brothers.

-His brothers both measured 2 weeks older at their "20 weeks" U/S s.

-The OB practice wanted to knock off 5 weeks. I only wanted to knock off 3 weeks. (I left that practice.)

-My third was born naturally (w/o induction) three days shy of my suggested EDD (the three weeks earlier one).

- The U/S report had an error margin of +/- 16 days. He was born exactly at + 16 days from the EDD suggested in the report.

AshasaurusRex · August 2012

Even if that head is big (which it probably isn't actually 4.5 weeks ahead big) just remember that your contractions, once you're fully dilated will help mold his head to fir through your pelvis and birth canal, there's a good reason those scull plates aren't fused yet. Good luck:).

amandaleigh1 · August 2012

I had a 7lb 4 oz baby with a 14" head. While my growth guesstimate was fairly accurate for his weight, there was nothing to worry about even with his rather large noggin.

sbevmc09 · August 2012

U/S are definitely not accurate, especially late in pregnancy. They can be off by up to 2lbs either way. Not sure about head measurements off the top of my head, but there is definitely a margin of error. Also, if they're off by even a little bit when doing their clicks it can add/subtract a lot. Maybe what you were seeing wasn't even their final measurements?

Also, anecdotal story similar to PP, I have a good friend whose baby was just "too big to fit" based only on U/S because doctor (who btw, had been talking to her about induction/C/S since she was early in her 2nd tri for convenience. Talk about red flags!) was sure that baby was around 10lbs. Baby was born and weighed 8lbs2oz.

mystrana · August 2012

sbevmc09:
Also, anecdotal story similar to PP, I have a good friend whose baby was just "too big to fit" based only on U/S because doctor (who btw, had been talking to her about induction/C/S since she was early in her 2nd tri for convenience. Talk about red flags!) was sure that baby was around 10lbs. Baby was born and weighed 8lbs2oz.

Yikes! Thankfully, my doctor has not said anything of the sort. He definitely stressed that the u/s was an estimate but as I've said, I'm just a bit of a worrier sometimes.