Large head circumference - future health outlook?

[Greycushion]

I am due next month and my baby’s head circumference has been tracking above the 90th percentile all along the pregnancy. Other measurements are around the 20th-30th percentile so there is a significant difference.

I have searched plenty of threads on here and one reason seems to be familial benign macrocephaly (FBM) - in other words, big heads run in the family. But this is not the case in our family.

For other posters where FBM is also not the case, I have searched their posts in the years following their pregnancy and it seems there is an association between large head circumference and later learning difficulties, tics and autism. Published research also seems to bear this association out. So, I am trying to be prepared.

I would be grateful if anyone who has been in this position can share any advice. What sort of things do I need to keep an eye out for and at what age? Thank you.

What percentile is he on for other things? I think you are reading too much into this. The percentiles differ by millimetres only so aren’t 100% accurate.

Yes, me!

My DD had a 99th percentile head circumference And 20th percentile everywhere else.

She was born with a 75th percentile head and 50th percentile everything else. There's nothing wrong with her and all is on track (she's coming up to 4)

As the previous poster mentioned, these measurements are based on millimetres and the accuracy can be a little out.

Its impossible to judge whilst baby is still in the womb. Measurements can be way off so you may have nothing to worry about at all. If baby is found to have an unusually large head when born then doctors will be looking for other indicators on the body if a genetic condition is at play,and perhaps a head MRI to determine brain involvement. But please don't think the worst. I was predicted to give birth to a 10lb+ baby with a head full of hair. She was 8lb 13oz and bald.

Have you mentioned possibility of baby having Hydrocephalus? Don’t want to worry you unduly but I wondered if this has been discussed??

Yes, I mentioned it at the last scan (32 weeks) and the sonographer said there were no signs but I will definitely be mentioning it again at my 35 week scan.

Femur length and abdominal circumference are both 20-30th percentile. I do understand that the measurements are inaccurate but I have had a number of NHS scans now and the head is consistently measuring above 90th percentile. So it is worrying me.

There are a number of signs that suggest hydrocephalus and a large head is just one of them. Sonographers look for signs of it, amongst signs for a huge variety of other concerns. Your sonographer has said that they don’t see anything else to suggest it which is a very good sign.

I had a child whose head was so large it was off the centile markings but the only issue it caused was needing bigger jumper sized in order to fit his head through.

DS2 had a massive head and looked a bit odd as a baby, now all good and just needs hats sized a few years older than he is

Not my own experience, but there was a woman at one of the baby groups I went to whose little
boy had a big head. I think at around maybe the 8 month mark? she thought he had an ear infection as he had become unsteady sitting so took him to GP, got antibiotics. GP called back later that day and asked if his head seemed big to her and told her to go to a&e. Turned out he had been having an issue with fluid on the brain and had to get a shunt inserted. Obviously don’t know all the ins and outs but they did say it was possible he could have some learning difficulties in the future. Don’t know how it all worked out sorry

My understanding was she always felt his head was big since birrh, don’t know centiles or anything though

DS's head was in the 90s Vs 50 for all other measurements at birth. At Uni now. Still has a massive head (and feet) but average height.

@2mumlife Turned out he had been having an issue with fluid on the brain and had to get a shunt inserted -this is the other term for Hydrocephalus. And you are right it is associated w learning difficulties.

@Greycushion not to scare you as I’m not a sonographer.

I’d trust a sonography whose medical professional over anything else they don’t take chances with things. If they’re not worried you shouldn’t be

It’s really hard to get accurate measurements before the baby is born. Don’t worry.

They will measure it properly when he is born and then at 6-8 week GP check. So you’ll know by then if it’s actually big or not.

My 6 month old DS head size was
off the charts at his 8 week check so the GP referred him to paediatrics. The consultant paediatrician looked at him and said he’s absolutely fine, perfectly healthy, just has a big head.

Sorry you are dealing this worry op. It's tough to have a cloud of worry overshadowing your anticipation of your new arrival. 💐

Sounds like it isn't a given there are problems so I hope your baby is fine like the other pp here.

My mum didn't have scans with me but looking at my baby pictures I am large of head and look a bit like a lollipop (a cute lollipop). I'm fine and don't look out of proportion now, but I don't really suit most hats and always need the larger so I do have a big head (though can't give you a centile).

Does it help you to think of it that by definition, 10% of the population have a head circumference over the 90th centile - 10 percent of all the people you know, all the people you see walking around everyday enjoying life, 10 percent of mums netters?

The chances of everything being fine are greatly in your favour. It does not sound as though there is anything structurally wrong. If the medical team are not concerned I would try not to worry.

I'm guessing it would've been picked up on your 20 week scan if your baby was likely to have a disability.

This sounds like ds! Absolutely nothing wrong just has a large head, looking now I think DH does too but he's 6'4 and has swimmers shoulders so doesn't look out of proportion. I did need an episiotomy.....

One of my DCs has a much larger than average head, but she is absolutely fine.
It wasn't picked up on any scans, and I don't know the percentile information, but maybe it would be picked up these days.

DC is in her late teens, and is of above average intelligence.

DD's head was and still is off the scale. She's at university and, in her refined phrase, 'needs fucking huge hats' but is otherwise just fine.

TBF we might have a different scale of 'fine' from other people, as her brother (who has a teeny head) does have autism.

But I do get the anxiety. Hydrocephalus would show up on a scan, I'm sure, as there would be visibly enlarged ventricles.

Well - not necessarily. Learning difficulties, tics and autism can’t be identified before birth. And there is a strong association and plenty of research which identifies a link between large head circumference and such future difficulties.

As I say, when I’ve searched previous threads on here, some from years and years ago, without exception (of the ones I’ve seen), the posters who posted to say their baby has a large head circumference either pre- or post-natally, then mentions in posts a few years later that their child has some form of difficulties. I guess I’m just trying to be prepared.

Both sides of the family are short in height and DH and I both have heads that are small-average size. So I know it’s not a case of familial benign macrocephaly. And as many have posted, hopefully it’s not hydrocephalus either as otherwise that would have been flagged by now - one would hope!

Well, DD is an exception, if that helps?

Yes, the exception stories are giving me hope!

There is also research that show that a large head correlates with IQ
https://publications.aap.org/pediatrics/article/118/4/1486/69076/The-Influence-of-Head-Growth-in-Fetal-Life-Infancy

Just to counter the worry a little

Hi OP I had issues with scans and a small head circumference. My OB (not in UK) measured it weekly and actually measured that it had gotten smaller!!! (Not possible I don't think) and I was referred to maternal fetal medicine for multiple scans and it always showed a small head. My daughter came out with a 50th percentile sized head. I spent so many hours worrying about it before she was born and it all ended up being ok, I'm sure your baby will be too xx