Causes of Cerebral Palsy

Congenital CP occurs before or during birth and accounts for 85-95% of cases. The following risk factors can be actual causes of CP. In many cases, the cause is multi-factorial. Having risk factors does not mean the child will have CP.

There are risk factors associated with congenital CP, but in some cases the cause is never determined. The following risk factors are associated with congenital CP. Low birth-weight babies are those weighing less than 2500 grams or 5.5 pounds or very low birth-weight babies who weigh less than 1500 grams, or 3.3 pounds are at the highest risk of having congenital CP. Low birth weight can be due to premature birth, infertility treatments which lead to twins or triplets which are often delivered prematurely, either unintentionally or intentionally. If one of the babies in a multiple gestation dies, the risk of CP increases.

Intrauterine growth restriction as a result of intrinsic placental problems or linked to maternal diseases such as high blood pressure or severe diabetes can cause CP. Infections of any kind, but especially a bacterial infection of the womb, viral infections such as rubella, cytomegalovirus, Zika virus, and high fevers during pregnancy can result in CP. Babies with other birth defects such as hydrocephalus or microcephaly and untreated bilirubin build-up that leads to kernicterus can be a cause or risk factor for CP. Maternal-fetal blood incompatibility is another reason that kernicterus may occur. Maternal diseases such as seizures, thyroid disorders, autoimmune diseases, or intellectual impairment are linked to CP. Birth complications such as uterine rupture or placental abruption which is when the placenta pulls away from the uterine wall before birth can both lead to severe blood loss, fetal distress, or hypoxia. The hypoxia must be severe enough to result in acidosis of less than 7.0 in order to be a factor in CP.

Acquired CP occurs more than 28 days after birth and represents a small percentage of all cases of CP. The most common causes of acquired CP are due to infections, underlying medical conditions, undiagnosed birth defects, or head trauma. Infections of the brain like meningitis or encephalitis during infancy can cause this type of CP. Motor vehicle accidents, physical abuse, and falls can result in brain injury significant enough to cause CP. Hypoxia or asphyxia from drowning or smoke inhalation may result in CP. Blood clotting problems and ruptured arterial-venous malformations can lead to bleeding in the brain that causes a stroke. Heart defects such as holes in its walls may result in a blood clot that travels to the brain shutting off oxygen. A child with sickle cell disease can develop a sickle cell crisis which decreases the oxygen to all organs including the brain. In conclusion, it is a severe external or internal insult to the developing 'early' brain that results in cerebral palsy.