Small fetal head circumference at 20 weeks scan

[Twinwife]

Hi, I had my 20 week scan and the head circumference was very small on the 5th centile. The femur length and abdominal measurements were small but 'normal'. No other concerns from scan except a 'placental make' (which I'd never hear of before)

Have to go back for a growth scan in 2 weeks-has anyone has this with a positive outcome?

I don't have experience, but the 5th centime means 5% of foetuses have the same size head. That is 1 in 20.
Of course you want to ensure he's growing, but (if it doesn't sound incredibly patronising) I wanted to make sure you understood the stat.

Kxx

Did they show any concern at your scan? I would say that even if 5th centile is small, it is on the small side of normal so on a scale of 100 "average" babies, yours would be on the smaller side of that scale. If he/she were "abnormally" small they would be outside of the centile parameter entirely. That's how I think it works.

As long as the measurements stay along the same line and don't drop further then all should be ok, I've had growth scans due to the abdominal measurement dropping down but the head has always been on the smaller side but tracking the same line and they are quite happy with this.

Hi
There was a little concern as there was a significant difference between the other two and head. I suppose there is nothing I can do but wait and see. I know that you can't interpret much from as one off measurement - but it still is a bit worrying!

Twinwife my 20 week scan with DS showed similar, and also very short femurs. I was given an extra growth scan just in case but the doctor was clear that there was nothing to worry about. It was me who insisted on googling until the birth, even though both DD and DH have quite short femurs and upper arms! DS also had a larger than average abdominal measurement at that gestation so it was out of proportion.

He came out fine and very in proportion and normal looking. I think even a mismeasurement of 1mm can make a big difference to the centile calculation.

If they weren't concerned enough to refer for a growth scan or do further investigations then I would take comfort from that and try to put it out of my mind.

Thanks altered. They have booked me for another scan in 10 days or so. But thank you, that is reassuring!

Hi Twinwife. I had exactly the same at my 20 week scan. Head was on the 3rd centile whilst everything else was on the 50th. I had to go back at 24 weeks and I've got another scan tomorrow when I'll be 28 weeks. Was your baby in a breach position? Apparently that can give inaccurate head measurements, they think that's what's going on with mine, though hopefully we'll find out a bit more tomorrow. Good luck, I've been really worried but hoping I'll get some answers soon and hope you do too!

Hi Catheric, yes it's breech. How was your 24 week scan?

My DS measured small with head and femur. I had extra growth scans but at nearly 4 years old he's a fit and healthy lad with quite long legs. He does still have a small head (as a health visitor kindly pointed out) but it's in proportion to his body as he's slim.

Currently 24 weeks and this one is measuring a pin head too ???? although it does have longer legs.

DP and I both have small heads though so I guess it just runs in the genes. They have these charts but I'm not convinced they're an exact science and babies do grow at different rates. You might find in 5-10 weeks everything has caught up etc. try not to worry.

Hi Twinwife. At the 24 week scan it was between 5th and 10th centile so looking a bit more hopeful, which is when the sonographer mentioned about the breach anomaly. At the 20 week scan it wasn't mentioned and the woman worried me stupid. DH found a study on line that linked breach presentation with incorrect head measurements, which also allayed my fears. Hope this helps

Thanks
How did it go today?

The head is now at 25th centile and so we've been signed off The baby was in a 'cephalic presentation' (??) and the (different) sonographer again said the anomalies were due to its previous breach presentation. I did say a head on the small size seemed preferable to me birthing it, lol.

Good luck with your scan, keep us posted!

That's fantastic! I will keep you updated!

My son always measured the lowest centile for femur and abdomen, but above for head circumference. I had growth scans all throughout my pregnancy and we were really concerned his whole body wasn't going to be in proportion! Luckily (although not so much for me with a 3rd degree tear!) his head was quite large but his legs were also long! Now at 4 months he's overall still on 5th centile for weight it definitely in proportion! It's worrying though when you're pregnant and unable to see properly how your child is developing xx

Had another scan today and the baby has grown, but along the teeny tiny line. All looks ok now so will book me in to monitor in 2 week. I feel much better

Hey, I’m just going through the exact same thing now. 20 week scan and head is measuring on the 6th centile, while the tummy and leg measurements were 50/60. Was everything ok in the end xx

Hi
Everything was perfect. She was a small 6lb 10oz even when a week later.
she has always been in the shorter side but otherwise a perfect 7 year old!