Accuracy of Ultrasounds Measuring Prebirth Weight - Induction?

I was also 5'6 120lbs when I got pregnant with my second daughter. They told me she was going to be around 8lbs. She was born at 10lbs!!!! The doctor said if she had known she was going to be that large they would have done a c-section. Why? She was born just fine. It was an easier labor and delivery than my first daughter who was only 7lbs and they had her weight predicted wrong also.

the day before I delivered I was told by an ultrasound tech that my baby was 8 1/2 lbs the next day I delivered a little 6 lb baby.

From what I understand they can be off by 1.5 lbs either direction and to be honest they have been pretty close to that amount will all three of mine, my first was estimated at 5lbs 4oz and she was 6lbs 8oz, my second was estimated at 6lbs 11 oz and he was 7lbs 14 oz and my third who was two weeks early was estimated at 6lbs 4 oz and was a whopping 7lbs 11 oz so they were never correct.

I was not induced with my first, but they were off by over a pound (they thought he would be about 7 pounds, and he was 8 pounds, 6 ounces). I was induced with my second, but not because of her size (she was measuring a bit small) but because of the placenta health. It was a good experience and I would do it again, but I was NOT induced early - I was induced in my 41st week. In any case, congrats on your new baby!

I was scared into inducing with my first at 41 weeks because they estimated my child to be so huge and I was afraid I'd end up in a c-section. She was about a pound smaller than they estimated. From what I understand it can be a pound off in either direction. I remember being so torn, not knowing what to do...it's a hard decision to make because you just don't know. Best of luck!

I would never induce based on an ultrasound estimate. They are frequently VERY off. If your baby is doing well in your womb, leave him there :) That is just my opinion though. Induction leads to a cascade of other unwanted interventions, and often c-section.

Your body is built to birth a baby. Let yourself get to an optimal stage where both your body and baby are ready for birth.

Good luck :)

K

I had an ultrasound when I was 39 weeks, and it showed that my baby was 9lb 8oz. So they induced me the next day, thinking that if I went on for another week it would require a c-section since the baby was so big.
Well... after 20hrs of pitocin and induced labor and not progressing, I ended up in a c-section anyway. My son was only 7lb 15oz.
So in my case - the ultrasound was off! and just maybe if I waited another week, I wouldn't have needed a c-section. who knows, but no regrets. My son was healthy and I had no complications.

The only thing I can tell you is that I have read and been told by lots of people that ultrasounds can be a couple pounds off in either direction. I personally would not go for the "big baby, let's induce you" bit. The doc could be wrong on your ultrasound for dating the pregnancy and the ones they're doing to monitor baby's growth could be off. Unless you have other reasons to be induced like pre-e or something, I'd tell them to let baby come on his or her own.

My early ultra sounds under-predicted my boys' sizes. BTW -- Ultrasounds after 20 weeks are progressively LESS accurate at confirming a due date. After 20 weeks, growth and size are more tied to the genetic pre-disposition of the parents or health conditions (i.e. gest diabts) and less related to EDOC.

Anyhooo...My early US said the 1st would be 8.5 lbs. He was 11 days late and was 10 lbs. My 2nd was estimated to be 8 lbs and he was 11 days early and was 8.5 lbs. Why do we make such big babies when we are 5'2" and 5'8"? No freakin' idea but the entire delivery room gasped in shock when these suckers came out.

Yep, they can be inaccurate. My last baby, born 15 months ago, was big 8lbs 14oz. I had ultrasounds every month and no mention of a big baby. I'm a doula and from what I have read, Monday and Tuesdays are the busiest for inductions with Wednesday and Thursday, next. Rarely are they done on Fridays, and almost never on Saturday or Sunday. The reason, doc's don't want to work on the weekends. So, some use whatever excuse they can, to induce, for their convenience, not yours. If you don't feel right about the docs decision, fight it, you and the baby are the patient. There are plenty of times they have induced, for size of the baby, and they have been wrong. Inductions also increase your chance of a c-section by 50%. Do some research and let you doc know how you feel. Good luck.

oh yeah I have, twice. Both times they said my baby measured big. The first time the doc let me go to 40wks and then induced. Babe #1 was 7lb 14oz, pretty regular. They were predicting him already over 8lbs at about 38 wks. The second time my dr was really concerned bc she said I showed even farther along than with my first and was only comfortable letting me go to 39wks....second babe 7lbs 11oz, so nah, not too accurate!! I talked to my dr about the inaccuarcy of late term ultrasound and asked her for statistics about when it was actually correct and when it wasn't, bc I really didn't want to be induced the second time as my first experience with induction was not too pleasant. She said about 60% of the time it wasn't correct and the baby was smaller than estimated, about 30% of the time it was nearly correct or the baby was actually bigger than estimated and about 10% it was just exactly correct. She said that if it was correct and my baby was large if there was a prob with the baby getting stuck in the birth canal at a point where there could be no c-section, I could sue her for malpractice and she would have no leg to stand on as she had information showing the possibility of a large baby. I really hated that my labor was not run based on my desires and especially not at all on my previous experience. I felt I was being pushed to have my baby before he was ready, which can lead to c-section, based on a litigation prone society. I was not a happy camper:( In the end, when she broke my water I went into labor on my own and had a beautiful experience:) It is very well known that late term ultrasound is notoriously inaccurate and yet that information is used to plan induction on a regular basis. However I have had two healthy babies vaginally and both were inductions, so it can be done!! Next time I am going to go another route and just get out of the whole your baby is big let us pull it out of you routine, but that is just me!! Good luck and congrats, it will go just fine whatever you decide to do:)

I knew my conception date exactly. And i was about 5'5", and had a HUGE belly. The US tech told me 2 weeks before delivery that my baby was already at 9 pounds. 2 weeks later I gave birth to a 7 pound 7 ounce peanut. Uh hugh. 9 pounds. Thanks for the scare.

I was induced with my first child, who ended up being born via c-section at 8lbs 13 oz. With my second child, I had an ultrasound 4 days before she was born and they estimated that she would also be approximately 8 lbs 13 oz. She was born via VBAC at 10lbs 3 oz. I have heard that ultrasounds can be off by 2 lbs in either direction, the techs are doing the best they can to estimate the weight of something hidden inside your belly. That said, you and your doctor know your body and medical history the best. The doctor wants to do whatever is possible to have a healthy, safe delivery, but you have to also make sure that you advocate for yourself to ensure that your preferences are understood. I'm not sure how early they were considering inducing, but more recent studies show that even delivering in the 36-39 week time frame there can be problems for children later in life. (Plus, for me, going into labor naturally was so much easier than the induction).

In my experience they are off. My daughter measured 3 lbs 9 oz on a Friday and I delivered on a Tuesday and she was 4 lb 15 oz, I delivered at 33 weeks. No way she gained more than a pound in four days.

If you are on Facebook-check out Dopplerdanger , Trustbirth and An EDD is an ESTIMATED Due Date not an EXPIRATION date!- there are actual studies, etc posted there that will give you your answers.

I also had a baby measuring large with a large belly. My doctor had an induction scheduled, but my guy came on his own 3 days before (which was 1 day before his due date). The issue with the big belly, according to my doctor, was that the head could fit through the birth canal, but then the belly can get stuck, making things very tricky and risky. You can't push the baby back in, so you have to figure out a way to deliver the baby. I actually had an ultrasound the morning he was born, and they were only off by 6 ounces (he was 8lbs 13oz, they measured 9lbs 3 oz). As it turns out, he did have a huge belly when he was born, but all went smoothly at the delivery. I would discuss your concerns with your doctor. Oh, as a side note, my second son was estimated to be about 7lbs 9oz, and was born 8lbs 8oz, so they can under-measure as well!

I would take the weight measurements with a grain of salt.

They were right on with my first - literally to the oz! But off by over a pound with my second...which was frustrating as I elected to be induced because I was scared of delivering a 9.5-10 pounder (turned out to only be 8lbs 9 oz).

My dr does a 37 week screen with me, because I typically measure ahead. They take several measurements from baby - head/shoulders, and some sort of measurements of my anatomy. They come up with a risk analysis for vaginal birth. While my kiddos were on the bigger side, I was always low risk and able to have vaginal birth. Perhaps you can ask if they do this type of calculation?

Yeah, I learned not to believe those. Atabout 30 wks, they said my son was already 4lbs! That would have meant, based on how they gain weight in the last weeks, that he would have been close to 10lbs born. That scared me to death! I was only about 2lbs and hubby was 8lbs (i was born at 28wks with my twin). i had him 10 days early due to pre-eclampsia, and he came out 7lb 9oz. biiiiiig difference lol. don't let the doc induce just because he thinks the baby is big...they really have no idea you know? and it could take away from your birth experience.

I went with my SIL for her ultrasound around 35 weeks and at that point they claimed the baby was already over 6 pounds and would be at least 11 pounds at birth. She went into labor at 38 weeks and he was a healthy 7 lbs 3 oz. Even if she had gone to 40 weeks he wouldn't have been anywhere close to the 11 lbs they were predicting. I don't think the predictions are accurate off of ultrasound.

My son was 2 1/2 wks early and the morning he was deliverd the perinatologist measured him at 7lbs 11 oz. He was in fact only 6lbs 11oz. That is a HUGE difference especially in an underdeveloped baby. He did have breathing problems after he was born and he was in the NICU for a few days, but letting him "cook" a little longer was not an option for us. His head and belly always measured large although he himself always measured EXACTLY with the week I was along. I would say that you should trust your gut. Do you have other kids to compare their birth weight to? I would say that they shouldn't even want to induce you until you are into your 39th week. Is the worse case scenario here a c-section because the baby is too big to deliver vaginally? (I would rather take that chance than have to visit my premature baby in the NICU for days or weeks) I would talk to your doctor about why they want to induce and what is the worst case scenario if the baby is in fact large at time of delivery.
Good luck!

It can depend on the type of ultrasound that you do. If you do one that is more detailed and stronger, the measurements will be more accurate. That being said, every tech I've seen (and on my last one, I saw her twice a week because of gest. diabetes) has told me that there is usually a margin of error around a lb + or -. Which was right on for our 2nd. They measured him at 9lbs and he was 10.

I've seen a lot of women who were supposed to have a "big baby" and ended up with a much smaller one. I've actually never known anyone who induced because of a "big baby" and had one as big as they said it would be (though I have heard they exist). I was pretty determined to have natural child birth, I didn't want to be induced, but I just don't understand the problem with birthing a big baby. I'm 5'4" and 130 lb when not pg (okay, so I haven't made it back down to that again yet...) and my last baby was 11 pounds and came out completely naturally on his own. I'd certainly ask a few questions and do some reasearch on my own before inducing for that reason. There's a good book called the Thinking Woman's Guide to a Better Birth that has a lot of good information on interventions.

K.

In my experience ultrasounds are not very accurate. My son was born at 32 weeks and the ultrasound showed him to be about 5 lbs. He actually weight alittle over 3 lbs. Also my sister in law was told by her doctor that he needed to induce her because her baby was measuring over 10lbs, he turned out to be 7lbs. The doctor induced her on July 2nd so the therory is that he did not want his holiday interupted.

Hi Mama-

I would not place so much faith in the ultrsounds (especially the later ones) and instead look inside yourself and get a pulse on what you personnally think is going on. I know this sounds a bit weird and maybe a bit "crunchy", but trust your instincts on this one...

I had an issue with my son where I felt like one particular doctor in my practice was "setting me up" for a c-section. Every time I saw him, he would complain about my measurements (they were running ahead of schedule) and based on a mid-pregnancy weight fluctuation, he was getting crazy. I was ordered for an US at 28 weeks and I told them that they would not be able see anything. This was my second pregnancy and I felt the baby move head down into the canal opening. He was not ready to be born but was perfectly positioned. Despite the tech's best attempts, I don't think the measurement she got was right - supposedly the measurements equated to a 5 pound baby and supposedly baby's gain like a pound a week (or some large number) in the end. Then, at 38 weeks, he wanted me to go for a third US stating that the baby was measuring "big". This time I refused. A big baby is defined as being over 10 pounds and I new in my heart this baby was not that big. Our son was born a beautiful and perfect 8 pounds 3 ounces - no where's near a "big" baby.

I would just be careful. Note, that you should also read up about the "cascade of interventions" that typically occurs when a birth is initiated with an induction. Some inductions turn out just fine, but it has been shown that more often than not it can lead to a c-section.

I would trust your instincts and just follow your gut.

Best wishes.
~C.

I had my daughter 6 years ago and had to have ultrasounds once a week because of gestational diabetes. The ultrasound said she was going to weigh 9lbs and she weighed 9lbs. I can't speak for all ultrasounds but mine was extremely accurate. Do you have gestational diabetes? This can cause the baby to grow at a faster rate. Good luck!

At 37 weeks, I was induced with gestational diabetes, due to a quote "very large baby". Estimated at 9-10 lbs, with 3 weeks to go, they have me delivery early. Lo and behold, my 7 lb 1oz baby girl was picture perfect. Their "guesses" are as good as your own!!!

I was told my first was going to be huge. I was similarly built as you (only 2 inches shorter, but small frame). I measured large. U/S showed large. He was born 2 weeks late, and was only 6 lb 14 oz. The doctor exclaimed, "Oh! He's just a little peanut!" However, I had a TON of fluid. Apparently, I make a lot of amniotic fluid. I always measure big. And, although I knew my dates very well, they dated him upon delivery. He only registered as 38 weeks at birth! So, he would have been a preemie if we had induced earlier. As it was, they induced me. I wish I had waited to go naturally. It was a LONG and difficult labor. He just wan't quite ready. BTW, all of my children have been born after their due date. I say my last one (#6) was "early" because she was only 3 days late. Other than the first and last, all the rest were born exactly one week late. Anyway, yes, they can be wrong. :)

I had ultrasounds every 3 weeks from 20 weeks until induction with my 4th child (due to various complications). The doctor (who was a perinatologist) was off by a pound, and even measured the baby the day before my induction -- he estimated over seven pounds and my daughter was only 6 pounds (but long - 19 inches, so maybe that is what threw him off). The doctor was off by a pound (the other way) with my second daughter -- she predicted 8 pounds and she was over 9. So I guess I have not had very accurate readings!

Yeah I never put much faith in the ultrasound measurements. Mine were never near what they said. My cousins wife supposedly got induced because of how large her baby was going to be. It wasn't anywhere near the size of my girls and for both I went two weeks over. My first was 8lbs 13oz and my second was 9lbs4oz. My Dr's office was never concerned with how big mine were. I guess I take that back, they did say at the beginning of my second pregnancy they were going to order and ultrasound towards the end of the pregnancy of second one because how big first one was. But I never got told I had to get induced. Went into labor on my own with both.

Oh and my sister delivered an 11lb baby, they never induced her either. They also said her first was going to be around 7lbs and she was 9lbs 5oz.

Drs WANT to believe there is a definitive for everything. They want to always be right. But the truth is, nothing is definitive and they are not always right. Your baby will start the labor when it's ready to leave... Why Drs cannot realize that and HELP women's bodies rather than try to change and control the course of a natural event?

Sorry I am late reading this. Regardless of whether ultrasounds are accurate or inaccurate, the American Congress of Obstetricians and Gynecologists (ACOG - the organization that most OBs belong to - hence FACOG- Fellow of ACOG) does not list a suspected big baby as a medically indicated reason to induce. Babies can be birthed in all sizes. Position of the baby is also extremely important. There are moms who have a hard time with 6 pound malpositoned babies and 13 pound babies that are born just fine vaginally. I have known women your size who vaginally birthed 11 pounders and even one with a 9 pound breech baby. Each baby and each birth is different.

I read an OB forum once where one of the OBs said he tells moms that want to know the size of the baby that "your guess is as good as mine." Some of studies showed that the mom's estimate of weight was the most accurate; followed by external palpitations by the provider, and last ultrasounds. I have also had a friend who was scared into an induction because the OB and ultrasound tech told her that her second baby was going to be bigger than her previous 9 lb 8 son. She was supposedly measuring big by ultrasounds, etc. Her second son was a good two pounds lighter.

Regardless of the accuracy of the ultrasound, your baby will "induce" labor when his lungs are fully developed and able to function outside the womb. I have a friend that delivered a 13lb 9oz baby vaginally and without drugs of any sort just a couple weeks ago! Our bodies are made to deliver babies. Congrats on your new baby and good luck with whatever you decide!!

The fact that your doctor mentioned inducing right off the bat is frightening. No one should be induced unless it's a medical necessity. Birth weight isn't a competition or indicator of the future size of a child. Little 6 pounders grow up to be 6'4"/250lb. line backers and conversely, 9lb. babies grow up to be 5'1"/100lb. jockeys. And yes those ultrasounds are off. I understand you needed more than usual due to your condition, but they aren't to be used as measuring tapes for size but more for developmental purposes. Relax and let your baby tell you when it's time to be born. 3 of my 4 were 9lbs. and up and I was never pressured to induce/have a c-section.

Mine were right on predicting.
Your size now and your husband's size now don't matter what matter's is your weights at birth.
My family have big babies, all of my self and my siblings were all 8-10 lbs at birth. I am very small 5'4" 115 pre pregnancy .

Weight and due dates are an approximation - always. Doctor's will always want to schedule the birth based on theirs/hospital's convenience. I'm surprised they haven't mentioned doing a c-section too =)

If it makes you feel any better, I was 5'1" and 125 pre-pregnancy weight and I safely, vaginally and with no problems, delivered a 9 lb, 1 oz baby and a 9 lb, 5 oz baby. I wasn't induced for either delivery and all my docs told me was that I had two fine, healthy baby boys.

The best news about big babies...they sleep through the night faster! Because of their weight at birth, my boys were sleeping through the night at 6 weeks to the day. Good times...

Good luck!

I wouldn't weigh too heavily on weight estimations from ultrasounds. My son they watched very closely because he was really small and induced a week early because of his growth. He was 5lbs 8 oz. With my daughter, I had an ultrasound on Wednesday and they guessed 6lbs 2oz and my daughter was born that Friday - 7lbs 11oz. way wrong! :) It is a guess, and that late in the pregnancy it can be hard to get an accurate weight.

Ultrasounds are awful after the first 8 weeks of pregnancy for accuracy. They SHOULD NOT BE USED FOR INDUCTION purposes. The silly tape measurement is as accurate in letting them know a rough estimate (if it will be closer to 6 or 10).

They induce because it is convenient for them and because most of them are not familiar with the latest research --they are too busy making hundreds of thousands of dollars running unnecessary tests and doing unnecessary c-sections. Size is only relevant for women who have their own internal size issues, and a Dr can determine this by doing an internal exam on momma, not by an ultrasound machine! Women are more than capable of having large babies. My easiest birth was with my 9.14oz son. My 6.15 oz daughter was awful. It has more to do with their positioning than with their size!

Short answer, your Dr is looking to induce you to control the "due date," i.e. he doesn't want to be woken up at 3 in the morning. There is no medically necessary reason based on size. It's a "False" excuse to induce and do c-sections in 99% of the cases.

Is there a reason why you are getting so many ultrasounds?

Well I had to go to a specialist doctor during my pregnancy because I had to much amniotic fluid and they guessed my baby would be 8.07 and my baby was 8.08! So in my case they were right on but I had the 3d and 4d sono's done every week from 30 weeks on.

I think the accuracy of you ultrasound weight prediction depends on when it is done in relation to when you deliver. For my 1st pregnancy, they did an ultrasound around the 36/37 week; prediction was for an over 8 1/2 lbs baby when I delivered--she arrived at 40 weeks, 6 days and was 7.7 lbs. So that estimate was a full pound off. For my 2nd pregnancy, I had an ultrasound at 40 weeks and they predicted 8.1 pounds; she was actually 8.8 lbs.

Personally, I would not want a 5 pound baby, especially since they lose weight after birth. If the estimate was that the baby weighed less than 7 lbs (assuming it could be 1 pound off and the baby could weigh 6 lbs and then lose additional weight), I would not induce unless medically necessary.

My doctor always says the mom is the best indicator of weight (if this is your first, it might be more difficult). I had a fetal measurement done at 37 weeks. The doctor said 7lbs 3oz....give or take 15oz. My son was born at 39w2d and was 7lbs 3oz. So, I think it's just a guesstimate! Are you worried about s/he not coming out? My first was 5lbs 13oz (vaginal delivery). My second was 7lbs 3oz (C-Sec). My third was also 7lbs 3oz (VBAC). I am a petite woman as well--5'2", 100lbs pre-preg. My sister is not much bigger than me and all of her kids were over 8lbs. It seems the fetal measurements guesstimate a larger baby--that's just my experience!

Best of Luck!

we just had our beautiful boy #3. with this one because it was a surprise i didnt remember my last period. so the same thing went on with me. blood work twice a week when i found out to see if hormones were increasing (note: previous history of misscaries) and first u/s a small sac but no fetal pole. week later fetal pole and sac and used an edd as the date given on my u/s Oct. 22, 2010. Now, at 36 weeks we had the baby weighed 7lbs and 7oz. the head was two weeks ahead of me but the femur which is where the accuracy of the edd is was right on target. we delivered at 37 weeks 4 days because i went into full labor (planned c-section was scheduled for Oct. 12). The baby weighed 8lbs 5oz and was 20.5" long (big baby for 37 weeks gestation). I was not too sure about my due date and even though I was miserable at the end I didnt want to push the delivery of the baby any sooner because of the possible missed due date. Fortunately nature took its course and i went into labor and had the baby. As for you, I would talk to your doctor about NOT inducing. An u/s can only be so accurate let nature take its course. If you start having complications then you need to do the obvious, but don't be forced to induce if the baby is still healthy.

I didn't have the ultarsounds to determine weight but I do know that measureing the belly does not work. Or at least not for me. My doctor kept telling us that we were going to have a 10 lbs baby because of how big my belly was. I went full term and had a bouncing 6lb 12oz baby. I even asked them where is the 4lb twin? lol
But I would think with an ultrasound it would be pretty close instead of using a tape measure thing. ;-)

For my two boys we did an ultrasound 2 weeks before my due date to see the size of the baby, so we could decide if induction was a good idea. Both of the ultrasounds were pretty spot on, they were both born at 9lbs and the ultrasound said 8.5 a week before delivery so they gained half a pound over that last week. I've just heard horror stories about getting to the moment of pushing out the baby, and the Dr. saying the baby was too big to deliver vaginally so I wanted to make sure they didn't get over 9lbs. My husband's father is 6'7 and I wanted to make sure the babies didn't get his genes:) My first came a week early, and we induced the second a week early and were both right at 9 lbs with no problems with induction.

My last anatomy scan showed my daughter being 7.5 lbs, that was at 40 weeks I delievered at 41 weeks and she was 9.3lbs so its not very accurate

I have health issues that I won't go into right now but I think they are fairly accurate. The more you have the more accurate they are according to my doctor and lab tech. I had so many I could have walpapered the nursery with the little pics they give you . The weight can be off by as much as 10%. My DD came out at 5lb 4oz and they said that she was just at 5lbs 6days before that. I would maybe hold off on an inductuction if you aren't sure. I for sure wouldn't let them cause labor anymore than 10days before.

With my son my pre-preg weight was 95 lbs (I was 19 and just 4'11"), I was told my one very obnoxious mid-wife that I was awful small to be as far along as I was and I would be lucky if my baby was 6 lbs. The other mid-wives stated I was measuring right where I should be. When I went in labor, the mid-wife (the nice one) felt my belly and said her estimate would be 7 lb 12 oz. My boy was 7 lb 15 1/2 oz! They never said what the ultrasound thought. With my daughter, they guessed she would be big based on me having GD, she was just 6 lb 11 oz. Not too big, not too small for either.

Early ultrasounds are the best determination as they are based on development, not size (since all babies are born at a differnt size). I have found them to be more accurate than the doctors' guesses for due dates.

Never experienced the size predictions showing large. Good luck.

my ultrasound weight was accurate. my due date was 2 wks after I delivered my doc wouldnt change it and i was doing ultrasounds once a week because I was old. I asked ultrasound doc If I needed another appointment and his response was why you will be carrying a baby. there will be nothing to ultrasound. told my doc this and he still wouldnt' change due date.