OK.. we've just been through all of this, so know what your going through as our DS has a head circ of 47cm which is on the 97th percentile (but his body/length is only on the 50th). What the doctors are looking for is Hydrocephalus (or fluid on the brain) which typically causes larger than normal head growth in babies.

It is a serious condition, but pretty rare and highly unlikely that your bub would have it and it generally causes other signs and quite serious delay in development. Many babies with this condition are 'off the charts' with head size. Still, the doctors like to cover their bums and check things out.

In all honesty, it has caused us a lot of stress and panic that we really didn't need - our DS was sent for ultrasounds to have a look inside his head. Turns out he just has lots of brains in there - hence the big noggin.

The most common cause for a big head is genetics - ie it is normal for your family! It really sounds as if your bub's head is in proportion to his body so like the PP, I'd say he is just a big baby.

Any Q's feel free to ask. We went through a really rough time with this as we had an idiot doctor that seemed to prefer to make us panic instead of letting us know how unlikely the condition is.