Perinatal and Postnatal Causes of Intellectual

DisabilitiesEducation of Students with an Intellectual Disability: Research and

Practice; Foreman, Phil; 2009

Perinatal Causes

• Perinatal causes of prematurity are the causes that happen right before and after a baby’s birth. This may be up to 4 weeks after birth• Prematurity – the main cause of intellectual disability associated with

this time period• Usually 36 weeks or less gestational period• May be classified by birth weight

• Extremely Low Birth Weight: < 2.2 pounds (<1000 g)• Very Low Birth Weight: 2.2 – 3.3 pounds (1000 – 1500g)• Moderately Low Birth Weight: 3.3 – 5.5 pounds (1500 – 2500g)

• Is the baby’s weight appropriate for gestational age?• Small for gestational age (below 10th %) – SGA• Large for gestational age (above 90th %) - LGA

Survival Rates

• Survival rates for premature babies have increased; however, that has led to an increase in the numbers of children with developmental disabilities• Ethical debates continue as medical science has evolved• It is not known whether the premature births are the cause or the

effect of intellectual disabilities in some instances. • Some developmental delays may not show up in LBW children until

later years• LBW, low APGAR scores, multiple births and complications in labor are

all risk factors during the perinatal period

Other Perinatal Factors

• Some may cause brain damage• Others may not cause physical or intellectual disabilities, but my

cause later learning disabilities, autism, or attention difficulties• “At risk” categories are helpful if it leads to provisions for support

with early identification

Postnatal Causes of Intellectual Disabilities

• Head injury – • Primarily accidents – traumatic brain injury (TBI)• Shaken baby syndrome – most common form of non-accidental head injury

that affects developing brains • TBI is one of the most preventable causes of intellectual disabilities

• Use of helmets• Car seats• Safe playgrounds• Awareness of shaken baby syndrome

• Problems may be temporary, lifelong, or result in death of a child• Severity of an injury has a direct correlation to the severity of the intellectual

disability or resulting death

Postnatal Causes (cont.)

• Infections• Meningitis – vaccinations have reduced the numbers of disabilities related to

meningitis and related illnesses in developed countries• Encephalitis – vaccinations have reduced these numbers as well

• Degenerative Disorders• Rett syndrome – appears primarily in girls who have developed normally for 6

– 18 months; is prenatal, but doesn’t show up until a child is older; high incidence of autism associated with Rett syndrome

• Seizure Disorders • More frequent and more severe seizures are associated with intellectual

disabilities than mild epilepsy

Postnatal Causes (cont.)

• Toxic-Metabolic Disorders• Lead poisoning – most likely to happen to children living in poverty or where lead is

still being used in gas and other chemicals; highly preventable cause of intellectual disabilities

• Malnutrition• Primarily in countries with chronic malnutrition• Relatively rare cause of intellectual disabilities

• Environmental Deprivation• Non-stimulating environments impact intellectual development (think long-term

institutional care, Romanian orphanage babies)• Questions arise about the impact of other risk factors – poverty, poor medical care,

diet, maternal use of drugs and alcohol, environmental toxins, etc.

Preventing Intellectual Disabilities

• Preventive and screening tests • Vaccinations• Reduction in numbers of children institutionalized has reduced

numbers of secondary disabilities• Genetic testing and screening tests will continue to raise ethical

questions