The majority of cases of failure to thrive (FTT) in infants and young children (under 2 years old) are not caused by disease.

Approximately two-thirds of all cases are caused by dysfunctional child-caregiver interaction, poverty, child abuse, and parental ignorance about appropriate child care.

Failure to thrive in children less than 2 years old is defined as failure to gain adequate weight, failure of linear growth, and failure to achieve some or all developmental milestones.

The health care provider may see poor hygiene, inappropriate clothing, and general lack of care. Some parents may feed their children unusual or overly restricted diets. Although the mother or other primary caregiver may appear concerned, the interplay and physical contact normally seen between mother and infant may be absent or distorted.

Factors that contribute to nonorganic failure to thrive include:

• young age of parent (teenage parents)
• unplanned or unwanted pregnancy
• lower levels of education (especially failure to complete high school)
• lower socioeconomic status
• absence of the father
• absence of a support network (family, close friends, or other support)
• mental illness, including severe post-partum depression