Cerebral palsy is a term used to describe a chronic condition affecting body and/or limb movement and the control of muscle tone and coordination. It is caused by damage to one or more specific areas of the brain during periods of brain development; there is usually no damage to the sensory or motor nerves controlling the muscles. The brain damage is not progressive; however, the characteristics of disabilities resulting from brain damage often change over time.

In examining the contributing factors that influence the occurrence of cerebral palsy and the specific causes of cerebral palsy, five (5) time periods need to be considered:

I. Preconception (parental background)
II. First trimester of pregnancy (0 to 3 months)
III. Second trimester of pregnancy (3+ to 6 months)
IV. Third trimester of pregnancy (6+ to 9 months)
V. Perinatal period and infancy (first 2 years post natal)

At a “critical time,” either a single factor or a combination of factors can contribute to or can cause damage to the developing brain. All factors have not yet been identified. However, a large number are known, and their most influential times of occurrence are being identified.

These factors and the times when they are most likely to have an impact on the developing brain, are listed below.

Preconception (Parental Background)
Biological aging (parent or parents over age 35)
Biological immaturity (very young parent or parents)
Environmental toxins
Genetic background and genetic disorders
Malnutrition
Metabolic disorders
Radiation damage

First Trimester of Pregnancy (0 to 3 months)
Early:
Endocrine: thyroid function; progesterone insufficiency
Nutrition: malnutrition; vitamin deficiencies; amino acid intolerance
Toxins: alcohol; drugs; poisons; smoking
Late:
Endocrine: thyroid function; progesterone insufficiency
Maternal disease: thyrotoxicosis; genetic disorders
Nutrition: malnutrition; amino acid intolerance

Second Trimester of Pregnancy (3+ to 6 months)
Early:
Infection: CM virus; rubella; toxoplasma; HIV; syphilis; chicken pox; subclinical uterine infection
Late:
Placental pathology: vascular occlusion; fetal malnutrition; chronic hypoxia; growth factor deficiencies

Third Trimester of Pregnancy (6+ to 9 months)
Early:
Prematurity and low birth weight
Blood factors: Rh incompatibility; jaundice
Cytokines: neurological tissue destruction
Inflamation and infection: chorioamnionitis
Late:
Prematurity and low birth weight
Hypoxia: placental insufficiency; perinatal hypoxia
Infection: listeria; meningitis; streptococcus group B; septicemia; chorioamnionitis

Perinatal Period and Infancy (first 2 years post natal)
Endocrine: hypoglycemia; hypothyroidism
Hypoxia: perinatal hypoxia; respiratory distress syndrome
Infection: meningitis; encephalitis
Multiple births: death of a twin or triplet
Stroke: hemorrhagic or embolic stroke
Trauma: abuse; accidents

© UCP Research & Educational Foundation, September 1995