Help! Worrying 😟 Baby percentiles

[BumbleAw]

I had a scan two weeks ago (32 weeks) and baby was 76th percentile overall, 95th head percentile, 50th percentile abdomen and femur.

Today at 34 weeks i had a different scan for a 4d picture and they also did measurements. They said he is 14th percentile overall. His head is still 96th percentile but abdomen has dropped to 24th and femur 4th. Can this be accurate and change this much in so little time !?

I had similar op (baby is six months now!) she has a smaller head than her sisters had(big headed family😂) and actually I remember so well my panic that she would have something wrong, but she was perfect. Also the scans can be so wrong too. My previous baby was coming up as off the charts big. She was 7lbs. My first they were killed telling me she was going to be under 6lbs, she was 9lbs.

Was one an NHS scan and one a private scan? I had an NHS growth scan on Wednesday where my baby was measuring 89th percentile, then I had a 4D scan literally just the next day at a private place where they measured him as being on the 78th percentile instead - I think it varies massively depending on who does it and how throughly they're checking the measurements etc etc

My SIL was told this both times and got in a real worry as they made it seem like it was an issue. Each time she had a normal sized baby with normal head measurement etc.

In my trust they don't talk about centiles as they don't think it's helpful or particularly accurate. I had no idea what size baby I was going to have until she came out!

Don't forget that the centiles when you're having a baby are personalised, so your baby's centiles won't be the same as someone else's. If you're lower BMI then your higher centiles could be quite a "normal" weight because they'll expect you to have a smaller baby. If you're larger then your higher centiles will be heavier because they will expect you to have a heavy baby.

For context, I've got raised BMI and in this pregnancy I'm being told that my first baby who was 7lbs 14oz was born on the 11th centile (50th with health visitors centile charts), and my 8lbs 10oz second baby was on the 32nd centile (75th according to health visitors. With my second they kept telling me I was having a small baby because she was predicted to be just over 7lbs, so small compared to what they thought I "should" have.

There is also a margin of error with growth scans of 10-15%, so I'd also suggest taking the scans with a pinch of salt and consider that it's possible that the measurements are slightly out.

@Welshcake15 - I’ve never heard of that. Do you have a link to a website explaining it please?

It's actually difficult to find information about the growth charts online and what it means. Most of the information I have is from discussions with my consultant in my second pregnancy when I was confused about how they could tell me that my first baby had been a low centile for weight when I had his red book from the health visitor that showed him as being on the 50th centile when he was born. There is information here about how the personal growth charts are calculated, but as I say, not what it really all means: ctmuhb.nhs.wales/services/maternity/pregnancy/growth-scans/

There is information about the accuracy of scans here: wisdom.nhs.wales/health-board-guidelines/hywel-dda-file/large-for-gestational-age-in-non-diabetic-guidelinehywel-dda-guideline-2022pdf/

This is not to say that you might not be having a big baby, but I'd recommend you have a look at what the predicted actual weight is at 40 weeks and also have a discussion about the accuracy of the scans.

It's all just guess work. None of my 3 matched up to the scans or measurements. My 1st....due to his measurements not matching his dates caused him to almost die. I was 42 plus 5 when he was born and he was very poorly. He measured small so they wouldn't induce me. I was told my middle child would be 4/5 lb max when born. She was a very healthy 6lb 13 and bang on due date. 3rd was healthy too despite a small bump and small measurements. I have a long torso apparently so that's why I never showed much of a bump. These things really need to be measured in a different way. My midwives only ever seemed to go on my bump rather than anything else. But after my 1st experience....I took charge.