Development Disorders

Causes and Risk Factors

Developmental disabilities begin anytime during the developmental period and can last throughout a person's lifetime. Most developmental disabilities begin before a baby is born, but some can happen after birth due to injury, infection or other factors.

Most developmental disabilities are thought to be caused by a complex mix of factors, including:

  • Genetics
  • Parental health and behaviors (such as smoking and/or drinking) during pregnancy
  • Complications during pregnancy or birth
  • Infections the mother might have during pregnancy or the baby might have very early in life
  • Exposure of the mother of child to high levels of environmental toxins, such as lead

For some developmental disabilities, such as fetal alcohol syndrome, which is caused by drinking alcohol during pregnancy, we know the cause. But for most, we don't.

The following are some examples of what we know about specific developmental disabilities.

  • At least 25% of hearing loss among babies is due to maternal infections during pregnancy, such as cytomegalovirus (CMV) infection; complications after birth; and head trauma.
  • Some of the most common known causes of intellectual disability include fetal alcohol syndrome; genetic and chromosomal conditions, such as Down syndrome and Fragile X Syndrome; and certain infections during pregnancy, such as toxoplasmosis.
  • Children who have a sibling are at a higher risk of also having an autism spectrum disorder.
  • Low birthweight, premature birth, multiple birth and infections during pregnancy are associated with an increased risk for many developmental disabilities.
  • Untreated newborn jaundice (high levels of bilirubin in the blood during the first few days after birth) can cause a type of brain damage known as kernicterus. Children with kernicterus are more likely to have cerebral palsy, hearing and vision problems, and problems with their teeth. Early detection and treatment of newborn jaundice can prevent kernicterus.

Who is affected?

The short answer is nearly everyone.

Developmental disabilities occur among all racial, ethnic and socioeconomic groups. Recent estimates in the United States show that about one in six, or about 15%, of children ages 3-17 have one or more developmental disabilities.