Growth scan

[sthitch]

How accurate are growth scans nowadays? I'm having one as showing 3cm over my chart, I'm also quite petite in weight and height so that could be why. How big does the baby have to be to start an induction and do they often go for a c-sec if showing too big? I'm 39 weeks.

Apparently they're not very accurate. But mine were spot on. Which I appreciate isn't very useful! Are you seeing a consultant?

I don't think so- perhaps if the scan shows a big baby?

It won't be long before someone comes along to say they are "notoriously inaccurate" but they are not bad really.

What is important is the trend. A once off measurement isn't completely helpful, but the trend and jumps in growth are more important.

Hopefully you'll see a consultant afterwards and be able to discuss the balances of risks and benefits of staying put, induction and section.

Here is the NICE guidance on induction.

www.nice.org.uk/guidance/cg70/chapter/1-guidance

In relation to macrosomia (big baby), it says:

"In the absence of any other indications, induction of labour should not be carried out simply because a healthcare professional suspects a baby is large for gestational age (macrosomic)."

But that is going to depend on you, the baby and your consultant. Hope all is well though.

My scan showed DD was 8lb 1oz, around my due date. She was born 8 days late weighed 7lb 2oz

Thank you - I had a position scan two weeks ago and was over on the chart then so I don't know why they didn't just measure then but she wouldn't, I was told 'well we can't shrink it' - I know they can't shrink the baby but there's no point measuring my belly if they don't mind if it's over. Thankfully the midwife today mentioned getting a growth scan which is good as I've been showing over for a while now!

The scan was after my midwife referred me as I was measuring 3 weeks behind. So I really wouldn't worry. I don't think they're very reliable

Hi sthitch,
The measurements are much more about picking up small babies than big babies. Very big measurements will also pick up too much fluid (polyhydramnios). The only evidence relating to inducing or delivering big babies is:

1. If a baby is estimated to be above 95th percentile, early induction can reduce the incidence of shoulder dystocia.

2. If the baby is estimated to be over 4.5kg, there should be a discussion about the risks and benefits of vaginal versus caesarean delivery (given the higher risk of failure to progress in labour or shoulder dystocia.

It isn't uncommon for fundal height measurements to be measuring big but scan to show a very normal sized baby!

Thank you for your reply, that sounds good - hopefully this means I won't be induces, I also hope that it's not too big! they have really struggled with working out its position for weeks which gives me some hope that it's not too big as surely it's easier to feel a big baby!!

For me my growth scan was incorrect. They sent me for a growth scan at 29 weeks as they were worried I was measuring 3 weeks over what I should of been went for a second growth scan at 32 weeks (last Friday) and she's exactly where she should be (the guy said it could be to do with how petite I am and the way baby was laid at the time) x

Thanks Chelsea - hopefully it will be accurate , I'm 5"1 and usually a size 8 so thinking that the only space the baby has is outwards!!

Mine was spot on. Advise from a lady who has two very large babies vaginally and via csection and also very petit and small framed is insist on induction or section before baby gets too big. My son very large boy was born naturally and it was very scary experience with shoulder dystocia. My dd equally large was born via csection and it was much better experience.

My scan showed DS to be 9lbs - he was 11.5lbs in the end.

I was measuring 51cm on my bump, so for me the scan was way, way off!

Also, they offered me an induction and I said I wanted a section because I knew in myself my baby was big if that makes sense. Whilst I'm tall I'm not very big, so I felt for me anyway it was the safest option.

ash GOOD CALL.
I would not want 11.5lbs coming out of my bits!

It's measured at 8.2lbs... they are happy for it to get to 9.9lbs before they will do anything... the consultant decided on this without even bothering to meet me so just have to sit it out, potentially 3 weeks to go if I go over. I'm quite upset about the whole thing.

Does anyone know the average weight gain at 40 weeks, 41, 42 ?

@namechanger2735 I know 🙈🙈 and he was sooooo long as well.

OP - ask to speak to the consultant, as I said in my previous post I was shown at 9lbs with about 2.5 weeks to go and my son was 11.5lb at 34 + 5! trust your instinct, if you're not happy escalate and explain your concerns.

When I spoke to the consultant they were really good, explained the risks of a section but in the end we both came to the conclusion it was the safest option.

39 + 5 not 34

Growth scan ( not tape measure ) accuracy +/- 20%

I recently had a growth scan at 35 weeks and was told the margin of error was 350g either way - so essentially my baby was between 5lb and 6lb 7oz. Its a fairly big range especially when then predicting birth weight.

I had gestational diabetes in all 3 pregnancies.

1st pregnancy the scan was saying about 10lbs at birth and my son was 7lbs 4oz

2nd pregnancy they said about 8lbs at birth and he was 7lbs 12 1/2 oz

3rd pregnancy I was measuring 50% centile at 33 wks and then at 37 wks scan was showing 95th centile. As the consultant said it didn't make any difference to me as I was already in for a c section at 39 wks anyways. Baby was born last wk at 8lbs 7oz.

Consultant did say for scan can show a big baby depends on way baby is lying. Also if baby he a full bladder etc can make baby bigger also.

My gut instinct was that it was a bit bigger for my height and weight but in the 7lbs region - so I was shocked to get that reading- even though I have a big bump (currently measuring 39.5) I put it down to water and placenta + baby!!

I didn't ask to speak to anyone as the decision had been made and it was such a big increase I have to get to that I thought there was no point in arguing - they know better than me as it's my first.

I just hope I haven't done anything wrong/I haven't been tested for diabetes but remained really thirsty so hope that's nothing to do with it?! I feel like going on a diet for the next 3 weeks even though I've just been eating normally!!

My worry is how big it can get in the next three weeks if I go over, if it's 8.2 now, what's the usual weight gain weekly? Looking at all my newborn clothes and feeling sad, I need him or her to come now so not to get any bigger!!

OP -

Take a breath it's nothing you've done, it's simply baby being baby!

I'm 5'10 and 10.9 stone normally, barely a size 10 and I had 11.5lb baby with a 51cm bump (which would measure at 51 weeks) .......I didn't have diabetes, I didn't eat unhealthy in fact I was back to my pre birth weight 8 weeks after giving birth! Sometimes these things just happen. As long as you and the baby is happy that's all that matters!

Speak to a consultant either way, peace of mind will go a long way regardless of how you give birth!

Thank you for your reply- it really does give me comfort! They didn't let me speak to one, I waited two hours and all I got was a chat in the waiting room after they showed my file to the consultant, I won't see anyone now until my due date - and that will be the normal midwife.

On the plus, I'm looking forward to dropping some weight as you mentioned- being tiny usually, I'm not used to being so big!!