What could make a twelve week fetus measure large?

We went in for our first trimester screening today and let me tell you the ultrasounds they have these days are amazing - it was all “oh look at its toes!” and “oh there’s the spine” and “here are some parts of the brain!” and “an earlobe!” and “nasal bone!” and the nuchal translucency looks good and it’s all happy and great and then they go to measure it and both the tech and the resident there practicing get really quiet and go “ohhh.”

Your first day of ultrasound school should be how never to say “ohhhh.”

Evidently the fetus is measuring a good week and a half older than it’s supposed to be. The thing is, I’m like 99% sure of our conception date within a few days - we were charting, there aren’t even that many days it could have happened that month even if the temp charting is off, etc. It’s almost certainly not that much older.

So obviously they’re sending this all over to my doctor (there’s also a fibroid that might force me to have a c-section, goddamn it!) and I’ll talk to, well, one of my doctors about it at my next appointment, but that isn’t for three weeks! I may change it to see “my” doctor, who I like very much, especially because of the fibroid thing, knowing she’s very supportive of natural childbirth. But obviously anything that sparks an “ohhh” is worrying the hell out of me and I want to learn more about what we’re "ohhh"ing about.

They were able to see an awful lot about the fetus and there wasn’t anything wrong with it as far as they could tell - everything is on the correct side of the body, etc. Is this a gestational diabetes thing? (I’m not overweight, normal blood pressure, 34, no known risk factors for anything that I’m aware of.) Can it just be a big baby?

Seriously. All medical personnel who administer tests for any reason should be taught this, especially when they are neither qualified nor permitted to interpret the results for you. (I’m looking at you, echocardiogram tech who said, “Hmmm…”)

Aside from which, as far as I know (which is admittedly very little), a big fetus means one of two things: you’re off on your conception date, or, what you’ve got yourself there is a big ol’ fetus. My kid consistently measured a week and a half to two weeks large throughout my pregnancy, even though like you, we were really, really sure of the date of conception. Result: one perfectly normal, 99th-percentile-sized baby, who’s grown into a perfectly normal, ever-so-slightly-above-average-sized kid.

What’s most likely to make a fetus measure large is the inaccuracy of ultrasound measuring techniques. At the end of pregnancy, estimates of the baby’s weight are often off by one, two, three, even four pounds (a friend of mine was told she was having an 11 pounder… he was 7 pounds). Imagine how much greater the margin for error is at 12 weeks, when the differences are so much smaller and the fetus–unlike 6 week embryos–is extremely active.

First baby? :slight_smile:

I agree with Sattua. If you’re that sure of your conception date, probably the tech messed up. If she’s inaccurately placing the marker, especially if she does it on both ends, she’s going to get inaccurate results.

My babies all measured a week or two off throughout my pregnancies. One was born on his due date and the “earliest” of the other two was 9 days. None of them were born clinically big but the biggest (8 lbs 10 oz) apparently only just missed whatever cut off they use for that designation.

Are you sure you need to wait until your next appointment to discuss results? My OB always calls when he receives results from an ultrasound or test, generally within a day of when he gets the report. The one exception was the 20 week ultrasound, which was performed by a doctor (not my OB) who answered questions right there in the room, and the final outcome was uneventful. Otherwise I’m sure my OB would have called on that one too.

My understanding is what **Sattua **said, the ultrasound measurements are only so accurate, especially that early. IANAD, etc.

12 weeks is pretty early; there’s a lot of slop between the estimated conception date and the difficulty in measuring the fetus exactly at that size, and being off by a week or two is not uncommon.

I think both of our suns measured big at 12 weeks, but as time went on, they leveled out pretty much on track.

BTW she did measure it several times as did the resident (who was there to practice.).

So any of you reassuring people have a natural delivery with a fibroid in the way?

My wife had a fibroid that they kept saying “might” be in the way, apparently sometimes fibroids grow during pregnancy? Anyway, at about 20 weeks they told us she would be fine. And she was. Delivery was a little rough, but not related to the fibroid.

My little bug measured big through pregnancy, and sure enough, she was 10 lbs when she was born. She’s still a hefty little baby.

What could make a twelve week fetus measure large?

I’m no medical expert but… big fat baby? I know that was the case with ours. Big chubby beautiful and healthy.

*Someone’s *got to be the biggest kid in the class. :slight_smile:

True dat!

Did they engulf any planets? :smiley:

A lot of the measuring of the fetus is guesswork. Towards the end of my pregnancy they freaked out because they thought my daughter gained like 2 lbs in a week. They hooked me up to monitors and freaked me the hell out by telling me she was going to be at least 9 lbs. When she was born she was a healthy 7 lbs but almost 23 inches long so it seems like her length was distorting their measurements. Don’t let them worry you too much and keep in mind it is mostly estimates anyway.

My understanding was that they’re a lot more standard when tiny though. It just seems to me that “tall baby” doesn’t merit “ohhhh”. Is there anything alarming it could be?

See now I started to make a joke with a link, but on second thought I realized that I’m not sure if expectant mothers would find that sort of thing amusing, endearing or slightly horrifying.

So instead I’ll just say I immediately thought of this recent story about the largest ( healthy ) baby born in California. He was one big baby!

Err…hope that doesn’t horrify Zsofia. I’m sure yours will be perfectly gold standard :).

My daughter also measured large. Then was born just two days past they point where she would be “premature”- at seven and a half pounds. And the doctor believed we’d gotten our conception date wrong. Big all through pregnancy, big at birth and not quite early.

But I’m pretty certain on the conception date - my husband was traveling a lot so there was a narrow window.

And, by the way, she was among the shortest and skinniest kids in her class…Now she is just “on the short side” and has caught up to most of her friends.

With my wife’s case it was pregnancy-induced diabetes, which disappeared upon giving birth. But she was under a strict diet to prevent the baby from ballooning to a point that a c-section was required. Baby came out nice and lean.

Repeat after me:
All measurements have an error margin.

All measurements have an error margin.
All measurements have an error margin.
All measurements have an error margin.

All measurements have an error margin.
All measurements have an error margin.
All measurements have an error margin.

I’m convinced that all they show on those screens are kaleidoscopic representations of Rorschach images. The techs just babble inanely along with the moving image, making up stuff and using big words that really don’t mean anything - much like an Olympic sportscaster. Then they give you a screen shot that looks like it came from a cheap mall photo booth and bill you $10,000,000.

Why, no, I’m not a real doctor. Why do you ask?

For some reason, I especially love this thread. I know I mostly lurk, but I have been seeing some of your names for so long - Zsofia, pbbth, even sven…and now we all have babies (Ethan was 13 months yesterday).