Cerebral palsy is a group of disorders that can affect brain and nervous system functions such as movement, learning, hearing, seeing, and thinking. It is caused by oxygen deprivation to the baby's brain in the womb, which can result from bleeding in the brain, infections, head injuries, or infections in the mother during pregnancy. Symptoms vary between individuals but can range from mild to severe impairment of motor functions on one or both sides of the body, and are usually noticed before age 2. Diagnostic tests help detect cerebral palsy but a full neurological examination is needed for an official diagnosis.