After Birth

1. Infections

   Certain infections during infancy and childhood can cause diseases such as meningitis and encephalitis that can affect the brain and result in intellectual disability.

2. Injury

   Physical injury such as blow to the head or a severe fall that results in brain damage may lead to intellectual disability.

3. Hormonal Deficiency

   A deficiency in the thyroid hormone can result in intellectual disability.

4. Jaundice

   Jaundice is a yellow tinge to the skin and sclera of the eyes caused by excess bilirubin (a substance produced by the breakdown of red blood cells) in the bloodstream that can cause brain damage and intellectual disability.

5. Malnutrition

   Inadequate nutrition during early childhood resulting in under-development of the brain can lead to intellectual disability.

6. Cultural-Familial Factors

   A lack of stimulation or a deprived environment during childhood may lead to intellectual disability.

7. No Known Causes

   Apart from the above known causes, there are many cases of intellectual disability that have no known causes. This is a very important point!²⁴