Some instances of cerebral palsy are genetic or the result of a mutation in the genes, according to Mayo Clinic. These mutations occur while the fetus' brain is developing.
Cerebral palsy also occurs if the mother has poisoning or an infection, such as German measles, chickenpox, syphilis, toxoplasmosis, says Mayo Clinic. Cerebral palsy may occur if the fetus suffers a stroke or his brain doesn't receive sufficient oxygen during childbirth, though this is unusual. The condition also occurs if the baby suffers an infection, such as meningitis or encephalitis, or a traumatic injury to the head. Sometimes, doctors do not know the cause of cerebral palsy.