Failure to Thrive :
Many children don't gain weight at the rate that they should, and this is known as failure to thrive. It is a sign of undernourishment and usually indicates that the child's diet does not provide the amount of calories that it should. It may stem from food intolerances, infections, metabolic disorders, household stresses, or other problems. Children and adolescents who experience failure to thrive may be shorter in height and have a smaller circumference of the head compared to other children of the same age. Failure to thrive slows down a child's development. The child may learn physical skills like sitting, standing, and walking later than normal. The development of mental and social skills may also be delayed. If the problem continues into adolescence, it can affect the development of secondary sexual characteristics.