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Readers Respond: How big was your baby supposed to be via ultrasound?

Responses: 45


Updated May 11, 2009

Ultrasounds are a very common test in pregnancy. They can give us a lot of information about how a baby is doing and what complications might befall a pregnancy. However, ultrasound does have its limits. One such limit is the inability to tell the size of the baby accurately. Despite this fact, many practitioners are still trying. This can lead to many complications including induction of labor for a big baby, cesarean section and other issues. Some estimates are that ultrasound can be off by more than a pound in either direction. Did you have an ultrasound for fetal weight? How did that knowledge affect you? Share Your Story

Big baby

Yes there is such thing as a person not being able to deliver big babies, my daughter which is my second was 9 pounds at birth, and she got stuck because she was to big so I has 3 nurses helping to pull her out, very painful delivery, I'm small just 5'1. Now with my 3rd baby I'm 34 wks and they say my baby is 6 pounds already, so because of my previous delivery and how hard that delivery was, I might get induce early to avoid the baby being to big and avoid a c-section.

Way off!!

My first was 37 wks 6lb 12 oz vaginally, but second was told that baby was estimated 9 lb 15 oz via US. OB put hands on my belly and said definitely big baby we need to c- sect tomorrow. After horrible c sect, baby girl was only 7 lb 10 oz. I'm now 39 weeks at different practice and getting big baby talk again. Not doing it. I'm healthy and never had any pregnancy complications. Unless there is a real problem or emergency...it's vbac for me.
—Guest Sarah

accuracy of fetal weight

hi for me i had a scan at 37th week and the baby weight according to nuultrasound was 3048 grams. but my girl was born after 5 days and her weight was 3.5 kg or 7.9 pounds. actually the measure fetal weight using bpd, fl and AC . and after 35 weeks these measuremnts dnt change that much or they move at slow pace....instead baby puts on fat... so chances of inaccuracy of fetal weight are high.
—Guest shumaila

Big baby boy :)

At my last ultrasound the tech said my son could range anywhere from 7lbs 8oz to 11 lbs, so I thought he would come out around 9 lbs. My husband kept saying 11 lbs. My first was a girl and she was only 8 lbs 9 oz, so I was surprized when they told me my son weighed a whopping 11 lbs 11 oz :) He has been growing fast too, only going to be 4 months and wears 12 months clothing.... wow!!!
—Guest Jenn Reed

way off

I was told at 38 weeks 4 weeks before I had my baby he was 8 pound 4oz I had him 14 days late he was 7 pound 1oz so way off
—Guest nadia

Way off

I was told that my baby would be between 7 & 8 lbs at delivery. He weighed 10 lbs. 3.5 oz. I delivered vaginally due to their wildly inaccurate calculation.
—Guest Amy


my ultrasound advice me that my boy baby would be weighing around five pounds 4 ounces and girl baby around five pounds 6 ounces....after giving birth a week later my girl was 4 10 boy was 5 5
—Guest smithwppp

Way way off

With my first baby I was told that he was gonna be 10lbs at birth delivered him at 38 weeks and he weight 8lbs 5oz then the sexing they said he was gonna be small on average 7lbs and delivered him at 39weeks he was 9lbs 3oz!! I'm so excited to know the weight of my third I'm 31 weeks now....
—Guest Shanais

very accurate

They told me my baby was 5 pounds 5 oz (had many ultrasounds cuz she messured 3 weeks behind) she was gaining bout 3-7 oz a week i had her less than a week later and she was 5 pounds 8oz the ultrasound tech at the hospital troed to tell me she was 7 pounds. My dr ultrasound tech said there was no wat.
—Guest trisha

Big baby's

My second child was 10 pounds 11 ounces all natural it hurt but didn't have any problms
—Guest Nat

Off the chart big!!

The midwife sent me for a ultrasound at 38 wks as my measurement was off the chart! They said he'd be at least 10lbs, they offered me a c-section which I declined! 5 days later he was born weighing 8lb 8, all that worrying for nothing!!!
—Guest Hayley


The monitored my son via ultrasound for several things last of which was weight. Throughout the entire pregnancy he was consistently in the 99th percentile which given genetics was not that surprising. I was told at my last ultrasound that if he were born at 400 weeks he would probably be about 10lbs give or take 1/2lb. My doctors said that past a suspected birth weight of 11lbs they preferred c sections but given my body structure and low risk they would let me try. As he was approaching two weeks late and the 11lb mark my doctors encouraged me to be induced to avoid the possible complications of both a large and late baby. I was medically induced 12 days late & delivered vaginally at exactly 42 weeks(long labor) with some tearing (2nd degree). He weighed 9lbs 7ozs- a full lb less than their prediction. He did not lose weight during those first few hours and days though as many infants do. Although I do slightly regret my induction, I realize that it was likely best.
—Guest Megan B

unnecessary tears

I was told my daughter was going to be a tiny baby and kept tabs on from 24wks (following an equally inaccurate fundal height measurement). I went home feeling scared and upset and just constantly reassuring myself that as I had only been 5lbs 9oz and perfectly fine there was no reason to panic. However you can't help worrying can you? I bought tiny baby and newborn clothes to fit any eventuality but she was 8lbs 5oz and 51cm long (not massive but big enough to not fit any of the stuff I had bought and by far big enough to negate all the worrying I had done!). I don't think they should tell you anything about the size if they cannot be accurate - they tell you try avoiding stress in pregnancy then are the cause of it unnecessarily. And all this sending people for intervention for big babies prior to labour even starting is appalling - the human body rarely gets it wrong and the individual mummy will know when it is time to accept help, but only after labour begins. xxxx
—Guest mummyto1and1intheoven

They Can be to big

I will be having an ultrasound to determine the weight of our growing girl. I know its just an estimate and will not take the answer to the bank however I will take it into account. My family has a history of big babies (over 10lbs) and just want to be ready. Yes I do believe our bodies can do more than what people may think but it can have its limits and yes it is a fact that a baby can be to big to pass. It comes down to weighing the information given to you and what you believe is best for your baby and you!

This is kinda sad...

I'm reading everyone's posts and I'm saddened by how many say "The doctor was afraid the baby wouldn't fit so I had a C-Section" Ladies, women can give birth to large children. My husband's great grandmother gave birth to a 13 pound child at 44 weeks. Vaginally. There is RARELY such thing as "too big for the birth canal." My 100 pound cousin gave birth to two over 9 pound babies naturally..and her mother gave birth to 8 children ranging from 7 pounds to almost 11 pounds all vaginally, at home with a midwife.
—Guest Sara

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