What are the risk factors?
There are some medical conditions or events that can happen during pregnancy and delivery that may increase a baby’s risk of being born with cerebral palsy. These risks include:
Low birthweight and premature birth. Premature babies (born less than 37 weeks into pregnancy) and babies weighing less than 5 ½ pounds at birth have a much higher risk of developing cerebral palsy than full-term, heavier weight babies. Tiny babies born at very early gestational ages are especially at risk.
Multiple births. Twins, triplets, and other multiple births -- even those born at term -- are linked to an increased risk of cerebral palsy. The death of a baby’s twin or triplet further increases the risk.
Infections during pregnancy. Infections such as toxoplasmosis, rubella (German measles), cytomegalovirus, and herpes, can infect the womb and placenta. Inflammation triggered by infection may then go on to damage the developing nervous system in an unborn baby. Maternal fever during pregnancy or delivery can also set off this kind of inflammatory response.
Blood type incompatibility between mother and child. Rh incompatibility is a condition that develops when a mother’s Rh blood type (either positive or negative) is different from the blood type of her baby. The mother’s system doesn’t tolerate the baby’s different blood type and her body will begin to make antibodies that will attack and kill her baby’s blood cells, which can cause brain damage.
Exposure to toxic substances. Mothers who have been exposed to toxic substances during pregnancy, such as methyl mercury, are at a heightened risk of having a baby with cerebral palsy.
Mothers with thyroid abnormalities, intellectual disability, excess protein in the urine, or seizures. Mothers with any of these conditions are slightly more likely to have a child with CP.
There are also medical conditions during labor and delivery, and immediately after delivery that act as warning signs for an increased risk of CP. However, most of these children will not develop CP. Warning signs include:
Breech presentation. Babies with cerebral palsy are more likely to be in a breech position (feet first) instead of head first at the beginning of labor. Babies who are unusually floppy as fetuses are more likely to be born in the breech position.
Complicated labor and delivery. A baby who has vascular or respiratory problems during labor and delivery may already have suffered brain damage or abnormalities.
Small for gestational age. Babies born smaller than normal for their gestational age are at risk for cerebral palsy because of factors that kept them from growing naturally in the womb.
Low Apgar score. The Apgar score is a numbered rating that reflects a newborn's physical health. Doctors periodically score a baby's heart rate, breathing, muscle tone, reflexes, and skin color during the first minutes after birth. A low score at 10-20 minutes after delivery is often considered an important sign of potential problems such as CP.
Jaundice. More than 50 percent of newborns develop jaundice (a yellowing of the skin or whites of the eyes) after birth when bilirubin, a substance normally found in bile, builds up faster than their livers can break it down and pass it from the body. Severe, untreated jaundice can kill brain cells and can cause deafness and CP.
Seizures. An infant who has seizures faces a higher risk of being diagnosed later in childhood with CP.