9 month old small head circumference

[NeitherQuietNorCalm]

My DS is the bright, beautiful light of our lives. He had his development check a few days ago. He's meeting all his milestones, been crawling since 5 months, is now cruising, babbles etc.

He was measured and is 18lbs and 72cm, so he's tall and slim like his dad. For comparison, I'm 4ft 10". But his head is only 42cm which is tiny. The HV didn't comment on it but I charted it and it's nearly off the lowest centiles.

I'm feeling paranoid now this means there's a problem. There's no prior measurements to compare it to. I've always thought he looks less "babyish" than most babies, he's very in proportion.

Am I worrying about nothing here?

I wouldn't worry. My DD had a small head at 8 months, it was something like 12% on the chart. She was a bright, lively baby and she is now a high functioning 8 year old with lots and lots to say! And a sweet little face, too.

Your DS will be absolutely fine. You must have seen some of those boys with those GIGANTIC heads? That's off the charts.

The first thing to do, almost certainly it will reassure you, is measure your head and his dad's head, smaller and larger heads run in families and can be significantly independent of other measurements in terms of genetic potential.

Also bear in mind that there is quite an error range in measuring head circumference. You want to get the largest measurement round, pretty much. Finally, head shape is another source of variation - a "taller" head will be narrower without any cause for concern.

(though, an unusually extreme head shape would be something to check with a doctor before ignoring).