When Brain Injury Occurs
The brain injury or abnormal development that causes CP can happen at three different stages:
- Prenatal (before birth) — the most common timing, accounting for about 70% of cases
- Perinatal (during birth) — about 20% of cases
- Postnatal (after birth) — about 10% of cases, typically within the first two years of life
In many cases, the exact cause of CP cannot be identified. Research continues to improve our understanding of how and why CP occurs.
Before Birth (Prenatal Causes)
Most cases of CP result from problems during brain development in pregnancy. These can include:
- Infections during pregnancy — such as rubella (German measles), cytomegalovirus (CMV), toxoplasmosis, or chorioamnionitis (infection of the membranes surrounding the baby)
- Placental problems — reduced blood flow or oxygen reaching the baby
- Stroke in the unborn baby — bleeding or blood clots in the developing brain
- Genetic factors — some genetic variations may increase vulnerability, though CP itself is not typically inherited
- Brain malformations — abnormal brain development for various reasons
- Maternal health conditions — thyroid problems, seizures, or other health issues
During Birth (Perinatal Causes)
While birth-related causes are less common than once thought, they still account for a significant number of cases:
- Oxygen deprivation (asphyxia) — severe lack of oxygen to the baby's brain during labour or delivery
- Prolonged or complicated labour — particularly if it leads to oxygen deprivation
- Premature birth — babies born before 37 weeks have a significantly higher risk, especially those born before 28 weeks
- Very low birth weight — babies under 2,500 grams (5.5 lbs) are at increased risk
- Trauma during delivery — though this is rare in modern obstetric care
After Birth (Postnatal Causes)
CP can also result from brain injury in early childhood (typically before age 2). This is sometimes called acquired CP:
- Meningitis or encephalitis — serious infections of the brain or its covering
- Head injury — from accidents, falls, or non-accidental injury
- Near-drowning — oxygen deprivation from submersion
- Stroke — bleeding or blood clots in the brain
- Severe jaundice — untreated high bilirubin levels (kernicterus)
Risk Factors
Certain factors increase the likelihood of CP, though having a risk factor does not mean a child will develop CP:
- Premature birth — the single biggest risk factor. The earlier the birth, the higher the risk
- Low birth weight — especially under 1,500 grams
- Multiple births — twins, triplets (partly due to higher rates of prematurity)
- Assisted reproduction — IVF and similar treatments (partly due to higher rates of multiple and premature births)
- Maternal infections during pregnancy
- Complicated delivery
What Does NOT Cause CP
There are some important misconceptions to address:
- CP is not caused by anything parents did or didn't do during pregnancy
- CP is not contagious
- CP is not typically inherited (though some genetic factors may play a role)
- Most children with CP were not deprived of oxygen during birth — this is a common myth
- Vaccines do not cause cerebral palsy
If your child has been diagnosed with CP, it is not your fault. In many cases, the cause is simply not known.