Stable brain injury. Anything that causes a stable injury to the brain (i.E a condition that does not progress) and affects movement in a child age 3 or younger can be associated with cerebral palsy.
Normal pregnancy. Nelson in the early 80's published unexpected data that showed more than half the patients with CP signs by age 7 had a normal pregnancy, labor, delivery and no cited problems over their 1st 7 yrs. This refuted the long pushed narrative that it was a birth injury. Unrecognised periods of poor blood flow, oxygen deprivation, infection or other factors are suspects. But sometimes we never know.
Genetic, maternal. There are several conditions associated with cerebral palsy. There may be brain abnormalities from genetic or chromosomal abnormalities. There may be a stroke which causes hemiplegia or one side of the body involved. The mother may have a clotting disorder causing a blood clot. The child might have a thyroid disorder.