Causes of Cerebral Palsy

Learning that your child has cerebral palsy often leads to one immediate question: “Why did this happen?” Understanding the causes of cerebral palsy can help families make sense of their child’s diagnosis, guide conversations with medical providers, and connect with appropriate care and support. While not every case has a clear or preventable cause, knowing what factors contribute to cerebral palsy empowers parents to ask informed questions and advocate effectively for their child.

This page explains the medical causes and risk factors for cerebral palsy in clear terms, with compassion for the families navigating this journey.

What Causes Cerebral Palsy?

Cerebral palsy results from abnormal development or damage to the developing brain. This damage affects a child’s ability to control movement, maintain posture, and coordinate muscles. The injury or abnormality occurs in the parts of the brain responsible for motor function, and it happens before the brain has fully matured.

The damage can occur at three different stages:

• Before birth (prenatal), during pregnancy
• During birth (perinatal), around the time of labor and delivery
• Shortly after birth (postnatal), in the first months or years of life

Most cases of cerebral palsy are congenital, meaning the injury or abnormality was present at or before birth. In many cases, doctors cannot identify one specific cause. Research continues to reveal how multiple factors, including genetics and environment, can interact to affect brain development.

Prenatal Causes

The majority of cerebral palsy cases originate before birth. Prenatal causes account for approximately 75 to 80 percent of all cerebral palsy diagnoses in the United States.

Abnormal Brain Development

Sometimes the brain does not develop as expected during pregnancy. This can happen due to:

• Genetic mutations or chromosomal abnormalities
• Brain malformations, such as incomplete closure of the neural tube
• Disruptions in the normal process of brain growth and cell migration

Recent research has shown that up to 25 percent of children with cerebral palsy may have identifiable genetic causes. This has expanded how physicians approach diagnosis, with genetic testing now recommended when the cause of cerebral palsy is unclear.

Maternal Infections

Infections during pregnancy can cross the placenta and damage the developing fetal brain. Infections known to increase the risk of cerebral palsy include:

• Rubella (German measles)
• Cytomegalovirus (CMV)
• Toxoplasmosis
• Herpes simplex virus
• Syphilis
• Zika virus

Many of these infections can be prevented or reduced through prenatal care, vaccination, and safe food handling practices.

Maternal Health Conditions

Certain health problems in the mother can affect the developing baby’s brain:

• Preeclampsia or chronic high blood pressure
• Thyroid disorders
• Poorly controlled diabetes
• Exposure to toxins such as methyl mercury

Managing chronic conditions before and during pregnancy is an important part of reducing risk.

Placental Problems

The placenta delivers oxygen and nutrients to the baby. When it does not function properly, the baby’s brain may not receive what it needs to develop normally. Problems include:

• Placental insufficiency (when the placenta is not functioning adequately)
• Placental abruption (when the placenta separates from the uterus too early)
• Intrauterine growth restriction, where the baby does not grow as expected

These complications may not always be preventable, but careful prenatal monitoring can sometimes identify and manage them.

Perinatal Causes

Perinatal causes occur around the time of labor and delivery. They account for approximately 10 to 15 percent of cerebral palsy cases.

Lack of Oxygen During Birth

Hypoxic-ischemic injury, also called birth asphyxia, happens when the baby’s brain does not receive enough oxygen during labor or delivery. While this is a widely recognized cause of cerebral palsy, it accounts for fewer than 10 percent of cases in developed countries. It is less common than many people assume.

Events that can reduce oxygen to the baby’s brain include:

• Umbilical cord prolapse (when the cord slips into the birth canal before the baby)
• Uterine rupture
• Severe drop in the mother’s blood pressure
• Placental abruption during labor

Not every difficult delivery causes cerebral palsy, and not every case of cerebral palsy results from a birth complication. Medical teams follow specific criteria to determine whether a lack of oxygen during birth contributed to a child’s diagnosis.

Premature Birth and Low Birth Weight

Premature birth is the single greatest risk factor for cerebral palsy. Babies born before 37 weeks of gestation, especially those born very prematurely, have a much higher risk. Low birth weight (less than 2,500 grams or about 5.5 pounds) also increases risk.

Premature babies are vulnerable to:

• Periventricular leukomalacia (PVL), a type of brain injury affecting the white matter near the brain’s ventricles
• Intraventricular hemorrhage (IVH), bleeding inside or around the brain’s ventricles

These injuries can disrupt normal brain development and lead to cerebral palsy. The earlier the birth, the higher the risk.

Multiple Births

Twins, triplets, and other multiples face a higher risk of cerebral palsy. This increased risk is largely due to prematurity and low birth weight, which are more common in multiple pregnancies. Complications related to sharing the womb and placenta can also play a role.

Postnatal Causes

Postnatal causes occur after birth, typically within the first few years of life. These account for approximately 10 percent of cerebral palsy cases.

Severe Jaundice

Jaundice is common in newborns and usually harmless. However, if bilirubin levels become very high and are not treated, the condition can progress to kernicterus, a form of brain damage. Kernicterus is preventable with proper monitoring and treatment. When it does occur, it often leads to athetoid cerebral palsy, a type characterized by involuntary movements.

Brain Infections

Infections that affect the brain or the tissues surrounding it can cause permanent damage. These include:

• Meningitis, an infection of the membranes covering the brain and spinal cord
• Encephalitis, an infection of the brain tissue itself)

These infections can occur in infancy or early childhood and may lead to acquired cerebral palsy.

Head Trauma

Injuries to a young child’s head can damage the brain. This includes:

• Accidental falls or car accidents
• Non-accidental trauma, including abuse

Shaken baby syndrome and other forms of abusive head trauma are serious causes of acquired cerebral palsy.

Other Medical Events

Other less common postnatal causes include:

• Neonatal stroke
• Severe low blood sugar (hypoglycemia)
• Metabolic disorders
• Near-drowning or suffocation

These events can occur in the first months or years of life and result in cerebral palsy that was not present at birth.

Risk Factors That Increase the Likelihood of Cerebral Palsy

Some factors do not directly cause cerebral palsy but increase the likelihood that it will occur. Understanding these can help families and doctors identify pregnancies and births that may need closer monitoring.

Before and during pregnancy:

• Maternal age (very young or older mothers may face higher risk)
• Fertility treatments that result in multiple births
• History of miscarriage or stillbirth
• Lack of prenatal care
• Smoking, alcohol, or drug use during pregnancy

During and after birth:

• Breech presentation or other abnormal fetal positions
• Prolonged or complicated labor
• Need for emergency cesarean delivery
• Low Apgar scores that remain low after resuscitation efforts
• Need for mechanical ventilation after birth
• Seizures in the newborn period

Not every child with these risk factors will develop cerebral palsy. Many children with cerebral palsy have none of these risk factors. The condition results from a complex interaction of factors, some of which are still not fully understood.

Why Identifying the Cause Matters

Knowing the cause or likely cause of your child’s cerebral palsy can:

• Help doctors anticipate other health concerns or developmental needs
• Guide treatment and therapy decisions
• Inform family planning and provide information about recurrence risk in future pregnancies
• Offer emotional clarity for parents seeking to understand what happened

In some cases, identifying a preventable or avoidable cause may also be important for legal or accountability reasons, though that is not the focus of this page.

The Role of Medical Investigation

When a child is diagnosed with cerebral palsy, doctors often conduct a thorough review of the medical history, including:

• Pregnancy and prenatal care records
• Labor and delivery records
• Newborn and early childhood health records

Diagnostic tests may include:

• Brain imaging, especially MRI, to look for structural abnormalities or signs of injury
• Genetic testing to check for mutations or chromosomal problems
• Metabolic testing to rule out inherited metabolic disorders

These investigations follow guidelines from leading medical organizations including the Centers for Disease Control and Prevention (CDC), the National Institutes of Health (NIH), and the American College of Obstetricians and Gynecologists (ACOG). As our understanding of cerebral palsy evolves, so do the tools and approaches used to investigate its causes.

Prevention and Early Intervention

While not all cases of cerebral palsy can be prevented, some risk factors can be reduced through:

• Comprehensive prenatal care and monitoring
• Vaccination against infections like rubella
• Treatment of Rh incompatibility between mother and baby
• Efforts to reduce preterm birth, such as progesterone therapy for high-risk mothers
• Careful management of maternal health conditions
• Prompt treatment of newborn jaundice
• Safe sleep practices and injury prevention in infancy

Early diagnosis and intervention, even before a formal cerebral palsy diagnosis is made, can improve outcomes and support development.

Finding Answers and Moving Forward

Understanding the causes of cerebral palsy is an important step, but it is only one part of your family’s journey. Every child with cerebral palsy is unique, and the focus quickly shifts from why it happened to how best to support your child’s growth, health, and quality of life.

At nybirthinjury.com, we provide trusted, evidence-based information to help families understand birth injuries and neurological conditions like cerebral palsy. Our goal is to connect you with the medical facts, support resources, and community connections that can make a real difference as you navigate care and advocacy for your child.

You are not alone in this, and there are many paths forward.