What are some causes for concern relating to my baby's growth?

Brain growth: Poor growth and nutrition will ultimately result in poor brain growth. This will can cause permenant decrease in IQ as well as permenant learning disability.

Too big; too little: Doctors like to see babies grow "the right amount". To follow the growth in length (height), weight, and head size, the doctor measures the baby at birth, 1 month, 2 months, 4 months, etc. . . .. The measurements are plotted on growth charts. If the charts show that a baby is too big or too little, then there may be a medical problem or possibly a hereditary tendency to be big or little.