Our infant son just turned 9 months old. He seems like a very normal child, is very happy, engaged and interactive. At his 9-month check up here's how he sized up:
* Weight: 22 lbs. (75th percentile)
* Height: 30 inches (Above 100 percentile)
* Head circumference: 50 cm. (Above 100 percentile)
He has no other indications: No bulge on his soft spot, no downward stare, no fever, detectable vision issues, etc. He seems fine - just a bit big.
He was born 7lbs 2oz and 21" long. His doctor says he's concerned about the *rate* of growth of his head since the 6th month visit. Having a large head isn't really a concern, but the rate of growth is. The doctor says he's *not* looking for a tumor and has scheduled an MRI for the middle of this month (best date he can get). His concern is hydrocephalus. After researching this I also see that this growth rate is a potential red flag for autism - but even there the fine details of that research says it's far from a guarantee.
The only other issue with our boy is he doesn't sleep through the night. This has been true since birth. Generally, he gets into a deep sleep anywhere from 4 (typical) to (occasionally) 6 hours. Then he cries and cannot calm himself down at that point (whereas at other points in during sleep he can calm himself). We have noticed that he's slept at night better in other places (e.g. while visiting family, on vacation, and even sleeping on the couch with me nearby).
Our theory is that since he's about the size of an 18 month old his caloric demands are too high for him to get it all during the day. So it may be that he wakes up hungry. We tried water-only for a while but that only delayed the next awakening. As for diet, he's getting solid foods. Another theory from a friend is that he's ready for whole milk as soy in formula products can cause problems (anecdotally speaking here).
I wanted to post this here to see if anyone is having or has had a similar situation with their child. And yes, I had a big head as a baby and there's a likely genetic link. But aside from that, we'd like to learn as much as we can about possible factors in his growth.