Inaccuracy of ultrasounds- then what?

[jeminijad]

I've read many times that a u/s to determine fetal size is often inaccurate... that it can be off by 1 - 2 lbs. I've read a number of threads that stated that the OB told mama that thet baby would be ten pounds, and the baby was born 7.5, etc.

IRL, my own DD was born at 8.1, when they had told me she would be close to 10lbs. I have an aquaintance who had a prophylactic c-section because of this same reason- 12 lb baby on scan, who was actually barely 9 lbs.

So has anyone rubbed this in their practitioner's face? Are they ever held accountable for their scare tactics? So many stories out there of major abdominal surgery for something that was just not true... this may be childish of me, but all I can think when I hear this is "well did you demand an explanation?"

I guess I want to hear stories!

[turnquia]

I haven't had any experience with that. We are doing serial growth ultrasounds on twins, but its more just to make sure they are growing... vs preventing them from getting too big.

And yes when further along they can be way off on weight. Like right now if they were to estimate my little boy based off femur length he's WAY larger than his sister. If they did just his head... he's way smaller.

So some of it too depends on how they are measuring... but just like the growth charts at the peds office, your kid can super duper tall on one chart, skinny as heck on another with a fat head ... but averaging all that together then it seems like you have one giagantic kid.. when really they aren't. (like they do on ultrasounds.. its an average of abdomen, head and femur sizes)...

So i'm not certain all docs are using it as "scare tactics". yes I'm sure some are. But really there is concern for mom/baby as well as the practioners license. I think we would get back to way more vaginal deliveries and less docs being so over precautious if there wasn't always the threat of liability and lawsuit involved.

I'm soooo tired so I hope this makes sense!

[MegBoz]

Ha! The Today show did a live CS on air a few months back. I was so hoping it was a scheduled CS for at least a fairly decent reason. Nope. Big baby. Estimated at 10#. I was SOOO HOPING baby would come out closer to 8 & the OB would be left looking stupid live on national TV. Nope, was like 9.5 or something - not quite 10#, but close.

The OB still looked stupid, IMO though because:
1. Even ACOG doesn't recommend prophylactic CS for big baby!!! & we all know ACOG isn't exactly acting to lower the overall CS rate.
2. The reporter asked her questions on CS in general, she said the rate was 25% "but it varies" (Um, no 32% nationwide!)
3. Reported asked common reasons for CS & she said "Big baby" was a common reason. Again, um, no, not according to ACOG that's not a standard of practice.

But, whatever.

As for your Q:

Originally Posted by jeminijad

So has anyone rubbed this in their practitioner's face? Are they ever held accountable for their scare tactics? So many stories out there of major abdominal surgery for something that was just not true... this may be childish of me, but all I can think when I hear this is "well did you demand an explanation?

The fact of the matter is, I really think it's so easy for them to point to something else as a valid reason. They could say the cord was wrapped around the neck & baby would have died anyway in attempting a vaginal birth. Whereas we know the truth is cord is wrapped around neck in like 30% of all births & is rarely a problem.

They could say the placenta was starting to degrade & not adequately support the baby with oxygen anymore.

Who knows what else they could say, but I'm sure they can. Just like poor women who are railroaded into needless inductions turned CS are led to truly believe they have Cephalo-pelvic-disproportion - that the baby never would have fit through their pelvis anyway (& that's why baby didn't descend & that's why they never dilated past X - not because of induction).

Or women left with CS for "failure to progress" are similarly left with the belief that their body was just 'broken' & failed & they "just never dilated" (again, instead of knowing the truth that maybe induction was the wrong course of action or the doc just wanted to get home to dinner or get home to bed, or they didn't dilate because they were tied to the bed flat on their back.)

So sad.

[caned & able]

Ultrasound scans are accurate for gestational age to the 20th week; after that, heredity takes over, and the date can be two to three weeks off.

Any woman confronted with an induction should ask for a Bishop's Score.

I often wonder how accurate those scales in the delivery room are, to tell the truth. How often would one suppose they are calibrated?

Also, I met Jay and Margie Hathaway of the Bradley Method at a health convention years ago. They were scheduled to film the vaginal birth of twins. The presence of twins was verified by several ultrasound scans. The babies' positions were drawn on the mother's stomach based on the latest scan.

The mother delivered one baby. ONE. Obviously a mistake was made.

After the Hathaways had put away their equipment, they went to the postpartum/recovery area to congratulate the mother "who was supposed to have twins, but did not", and no one in the recovery area had a record of a mother with that description. The records were changed that quickly.

This story is also documented in a newsletter by Dr. Mendelsohn regarding ultrasound prior to 1985. If you think ultrasounds readings have become more accurate in the last 25 years, why are we having this discussion now? Technicians and doctors have learned from prior mistakes. Ultrasound technology has been around for 70 years, since WWII.

[Cassaba]

I refused a 32 week "growth" ultrasound for that reason. It seems that the more information they have, espcially when it's potentially erroneous, the more likely you are to face interventions.

[Mama2mc]

My OB's estimation was quite accurate, and mostly she was checking for growth; she never used any scare tactics, nor suggested c-section, so it wasn't a problem for us.

[turnquia]

Originally Posted by Mama2mc

My OB's estimation was quite accurate, and mostly she was checking for growth; she never used any scare tactics, nor suggested c-section, so it wasn't a problem for us.

I think really this is what it needs to come down to. Finding a provider that we work well with, but yet can trust their professional medical opionions for when they are needed.

In the case of the lady with twins, I wonder what the heck they did that was wrong where they got that awkward results. Like did the u/s tech have some sort of double image thing set up on the screen?

As someone pregnant with twins that seems pretty impossible to screw up. Especially if you get an earlier scan.. and you can see very very clearly two babies, two sacs, two placentas both babies moving different ways... and in our case different gender's

[bella99]

I had a friend who's doctor, based on her fundal height (no u/s) was measuring the baby at close to 10 lbs at 36 weeks.

A week or so later, she was induced for pre-e, and ended up with a c-section (a very positive and respectful c-section, but that's another tale). The baby was just over 5 lbs, but what was causing that fundal height? A large fibroid that was blocked during her 20 week u/s by her placenta and the baby!

She's pregnant now and and her doc are planning for a vbac, but the c-section really worked out in her favor.

[jeminijad]

I suppose it is impossible to 'call out' any medical professional on anything that they stated verbally... unless you are getting copies of your records as you go, and that ain't happening

[MegBoz]

Originally Posted by jeminijad

I suppose it is impossible to 'call out' any medical professional on anything that they stated verbally... unless you are getting copies of your records as you go, and that ain't happening

That's an interesting point - but in the case of women who have a scheduled CS for "suspected fetal macrosomia" (aka "big baby") wouldn't there be a paper trail? If they schedule a CS with no labor, doesn't there need to be a reason listed? So I would think in that case, the OB couldn't really "hide" the fact that they'd estimated a big baby.

[jeminijad]

For those who wanted a section, or didn't care either way, or could be easily convinced.... okay.

But if they told me my baby was 12lbs, I had a scheduled csection for that reason, and the baby was under 10- I promise I would be screaming! There have got to be some others on this forum who think about this.

[kate3]

I had serial growth sonos with all 3 pregnancies due to pre-existing hypertension. All 3 were dead on accurate, within a few ounces.

[nmelanson]

Oh man.... I shouldn't even get started...

I watched the US tech do his measurements and his starting points were WAY OFF... as in, not even on the baby! Even I could see that! I told my midwife this and she did NOT make a note of it. Later on, the resident pediatrician called my unborn baby a "little fatty". On the records it states that he was asymetrically macrosomatic. When he was born, it was evident that he as neither a fatty, nor asymetrically macrosomatic. No one apologized for not listening to me, nor their rudeness (of calling my baby a fatty)- nor did they change the records to state that he wasn't macrosomatic after all. So, if I have another baby, I am likely going to have a whole bunch of extra ultrasounds to see if the baby was macrosomatic like the last one was - all because of the inaccuracies of ultrasound and the unwillingness to admit it!

I have so much more to say.... but I'll leave it at that!

[homemademom]

I've heard the stories about late term ultrasounds being inaccurate, but I've had one with two of my babies and they were both spot on (8 1/2 lb babies each time). The first ultrasound was at 34 weeks, the second at 37 wks. So ? Maybe it has to do with the tech (in my case, one was an u/s tech, the other was an OB)??

[jeminijad]

I am certain that some techs are more skilled than others, just like every other job. But it isn't like choosing a plumber, where you can check angie's list! That one person's adeptness, or the repair of their machine, etc can result in drastically different care for a mother and child.

It is good to hear of those who have had accurate ultrasounds- but in my personal experience (admittedly, only about a dozen,) I have yet to come across one that was within 1/2lb.

[Sijae]

I say don't do ultrasounds at all and you solve the whole problem.

[nia82]

Early dating ultrasounds are pretty accurate, as at that point in time most babies are the same size at the same gestation. Later on, not so much. I wouldn't consent to a c-section because of suspected fetal macromesia, like never. I'd attempt a vaginal birth and see and wait and wouldn't mourn the labor pains if I really ended up with a section, cause I tried and then know for sure, while ultrasounds can be soooo off. I know several women who were told 11lbs or 12lbs and out comes a 7 pounder via c-section... I don't think you can make the doctors responsible for anything, as you signed consent papers.
Personally, I only do one ultrasound around 20 weeks as anatomy scan which I keep as short as possible. I was even comfortable skipping all of them, but DH wants to know the gender badly. I have it with an obgyn though, no ultrasound tech. I didn't want an early u/s nor need it, I know my o-date, and without that, they would have had to work with my LMP. But I'm at a birthing center with midwives, they don't even do ultrasounds, they refer you if you request it only.

[tireesix]

Ok....

First baby in 2004, they did ultrasound at 11 weeks (actually 9 weeks) apparetnly she was small compared to dates which is understandable considering I had a 6 week cycle and they were basing my pregnancy on a 4 week cycle. They kept insisting baby was small, I kept saying their dates were off, so, ultrasound was accurate, just read wrong.

Second baby, scanned at 12 weeks, they decided I was due 6th November, I said 'thats IMPOSSIBLE', they said 'its what the scan says', I said (embarrasingly), I was rarely having sex at that point, in fact, I remember the day I ovulated which happened to be the day after I had sex so I am due 6th November. Scan was out by 3 weeks.

3rd baby, scanned due to possible upside down baby at 39 1/2 weeks, was told baby would be 10lbs at least, baby was born 3 days later weighing 7lb 6 ozs. Couldn't say anything because I had a homebirth and never saw the consultant again.

[purplepaisleymama]

With my first I had many u/s, the day I was induced they said that he was 4.5 - 5lbs and would need to go to the NICU. They prepared for a small for dates baby with many issues..... he was 7lbs 13oz, my biggest baby.

I have not had any other u/s at the end of pregnancy, so I can't say what the accuracy would be. I did have one at 28 weeks this pregnancy and they said that our little one was 3lbs, I am sure that she was bigger than that, I have been measuring larger than I did with my last consistently this pregnancy and I was almost as big as I was when he was born and he was 5lbs 7oz at 35 weeks.

I am not sure how much I would trust measurements unless it was always by the same tech and on the same machine, there seems to be a big gap in results with different people. When we had a 20 week this pregnancy the tech and md had different measurements, not drastically different but enough that they were thinking of changing the date by a few days.


With the early u/s this pregnancy (to check viability as this pregnancy is after 3 mc) I had measured a few weeks ahead, the 20 week I measured slightly ahead..... for me very odd as my previous pregnancies were all smaller than dates babies, so it will be interesting to see what will happen this time. I think that due to my o date being almost a week earlier than average and the measurements being larger than I usually am I am farther along by at least a week if not more.

[mmaramba]

I'm not even sure it's terribly dependent on how skilled the tech is, honestly. You'd expect them to be accurate (with a 1/2 pound) a significant percentage of the time, even if they simply guessed a number between 6 and 10 pounds.

I have a question-- how can you tell from an ultrasound how HEAVY a baby is? I'm honestly asking. Is there something I'm missing?

You can't guess weight consistently within 10-20 pounds by looking at a grown person outside the womb, and that's generally 5-20% of their weight. That's the equivalent of 4 oz to 2 lbs for a baby, and again-- that's outside the womb, a LOT easier to see than via ultrasound.

I'm 5'2" and weigh about 160 (I'm not pregnant). I don't visually present as significantly overweight, I typically wear a dress size from 4-8, and even my largest designer slim-fit jeans are a 30 waist. The largest non-vintage item I own, period, is a high-end size 10. Yet I would be considered clinically obese if I gained 3 pounds. Everyone who has seen me in person is surprised at my actual weight-- I've even had more than one stranger check my ID (which actually says I weigh 155, LOL) and ask if I've lost "a lot of weight" recently. I guess they could be feigning surprise and fudging downwards, but I buy it. I have a lot of muscle (concealed by some lower body fat), and dense bones.

CPD (and "CPD") has little to do with weight anyway, so WTF? Sure, a baby weight of 14 pounds is probably correlated to a big head, but under 12 pounds or so, who knows? My head was FAR bigger than my brother's, and I was only 12 oz heavier. And of course, positioning is the far more significant issue, but little if any attention is paid to that.

I don't think these estimation errors, which tend to skew over rather than under, are made with the conscious intention of scaring women into C/S. But I do think that when you're a hammer, everything looks like a nail, and when you're an OB, almost everything looks like a potential C/S, and that tends to trickle down to techs, who may "see" bigger babies than are there, on average. You're sued for the C/S you don't do, not the C/S you do, and all that.

But the bigger question is why this is even an issue. Why more than the most fleeting bit of attention is paid to weight estimates-- not to mention ultrasound "redating." And the answer, again, is the vicious cycle of CYA obstetrics has caught itself in the middle of. When in doubt, it's a C/S. Do that enough and you've never even seen a woman under 5'2" give birth vaginally, so the next 5' woman you see, start preparing her at her first appointment for her probable C/S. You've never seen an uninduced woman give birth, so you start to think all 41+ week babies will die without one. Etc., etc., etc. But when that baby the mother thought was at 36 weeks, but you "re-estimated" at 40 weeks-- or that 5 pounder you estimated at 9 pounds-- comes out needing a ventilator? Thank goodness they were in the hospital! Otherwise they would have died!