My nephew had an abnormally large head when he was a baby. He had a cat scan when he was about 15 months and everything turned out to be ok. He also had a lot of trouble eating too, he would throw up at least once a day until he was about four years old. The drs thought his eating problems were neurological, so that combined with the size made them worried which is why he had the scan. He's seven now and perfectly normal.
I wouldn't worry about your son right now. Three months is a long time in the life of a baby and a lot of things can change between now and then. You also don't want to spend those three months being so worried about him that you miss this highly developmental time. He will only go through this time once, and you certainly don't want to miss it! I'm not saying that you are going to do that, I just know that I need to be reminded sometimes of what's in front of me now not what will be in the future.
at 6:51 PM on Feb. 9, 2009