Prenatal, perinatal and postnatal etiologies of physical and health impairments.

Two general groups play a role:

• genetic factors
  • passed on from one or both parents
  • not always visible in the parents
  • recessive genes
• factors outside the fetus -teratogens- 

  Prenatal

  • mother's inadequate medical care 
  • mother's diet
  • mothers smoking, drinking, drug use

  Perinatal

  • trauma
  • anoxia -oxygen debt-
  • strangulation

  Postnatal

  • bicycle, car or other accidents involving the spinal cord and head injuries
  • infection -bacterial and viral-