Baby boy's head measured 35.5cm at birth, 36.5cm at 2 weeks and 39cm at 1 month. it was measured by 3 different people. doctor said his head feels normal but she will recheck at his 2 month appt. worried of possible hydrocephalus?

Besides to the difference in the measurer's technique, your baby's head circumferences at those times are within normal limits so I think your concern is not worth it. Furthermore, you should not worry about something which you can't help to affect the outcome at this time.

This is within the upper normal range for infants at that age. Measurements will also vary some by who does it and can vary at the same encounter. The pediatrician can also readily discount the idea "hydrocephalus" or other expansion under pressure by simple measures on physical exam.