The cause of cerebral palsy (CP) is often unknown, particularly in cases of congenital CP, a type that develops either prior to or during the birthing process. However, researchers have identified several factors that could increase the risk of this disease.
These risks are broken down into three different categories:
- Pregnancy factors related to CP
- Birth-related factors that can increase CP risk
- Post-birth CP factors
Pregnancy Factors Related to CP
Some of the risk factors associated with CP are related to the mother’s pregnancy, from conception to delivery. These include:
- Assisted reproductive technology (ART) infertility treatments. Children conceived via certain infertility procedures have a higher risk of developing CP. This is largely because infertility treatments often result in multiple births or premature delivery, two factors associated with an increase of a child’s risk of cerebral palsy.
- Maternal infections and fevers. If the mother develops an infection or has a fever during the pregnancy, this could also increase a child’s risk of CP. This can occur with chickenpox, German measles, cytomegalovirus, a pelvic infection, syphilis, herpes, or the Zika virus. The infection or fever causes an increase in cytokines, or small proteins, which then creates inflammation in the fetus. This inflammation leads to the brain damage characteristic of CP.
- Toxoplasmosis. Toxoplasmosis occurs when the mother has developed an infection from parasites commonly found in the feces of infected cats, some soils, and contaminated food, and this has been found to potentially lead to CP.
- Maternal thyroid issues. Although research is unclear as to whether a thyroid issue during a mother’s pregnancy may increase CP risk, some experts suggest that it is a potential cause and needs to be considered.
- Blood type incompatibility. Sometimes the mother’s blood type is different than that of her developing fetus. This is called Rh incompatibility and refers to if the mother’s blood is positive and the baby’s is negative, or vice versa. If it occurs, the mother’s body makes antibodies to fight off her baby’s opposite-type cells, resulting in brain damage consistent with CP.
- Exposure to toxins. If an expectant mother is exposed to certain toxins, this could increase the child’s risk of CP. One such toxin is methylmercury, a toxin that one study found to be elevated in certain geographic areas, such as around the Great Lakes.
- Excessive alcohol consumption. After studying 23,573 live births, research published in Developmental Medicine & Child Neurology noted that “heavy maternal alcohol consumption is a direct cause of pre/perinatally acquired CP, and an indirect cause of postneonatally acquired CP.” Though its results were specific to non-Aboriginal children, the study suggests that alcohol consumption by an expectant mother can raise CP risk.
- Maternal seizures. Mothers who have seizures have an increased risk of birthing a child with CP.
- Maternal intellectual disabilities. Mothers with intellectual disabilities also have a higher risk of having a baby diagnosed with CP.
Birth-Related Factors that Can Increase CP Risk
Other factors that can increase a child’s risk of CP are more related to the birthing process. They are:
- Preterm birth. According to the Centers for Disease Control and Prevention (CDC), a child has greater chance of developing CP if he or she is born prior to the 37th week. This risk increases more for children born before the 32nd week.
- Low birth weight. The CDC also indicates that children who are born weighing less than 5.5 pounds have a higher risk of CP. If they weigh less than three pounds and five ounces, the risk is even greater.
- Multiple births. If a baby is a twin, triplet, or other type of multiple birth, his or her chances of a CP diagnosis increase. The risk is compounded even more if one of the other babies is stillborn or passes shortly after the birth.
- Birthing complications. If the placenta detaches, uterus ruptures, or there are issues with the umbilical cord during the birthing process, the newborn may not get the oxygen he or she needs, resulting in brain damage and, subsequently, CP.
- Breech delivery. A breech delivery, which is when the baby is born feet first as opposed to head first, could increase the risk of CP as well.
- Seizures. Babies who experience seizures are more likely to develop CP.
Post-Birth CP Factors
Even after the birthing process, there remain certain factors that could increase the likelihood that a child will develop brain damage consistent with cerebral palsy. Here are two to consider:
- Jaundice. Jaundice is often recognized by a yellowing of the whites of the eyes and the skin. It is caused by a buildup of bilirubin—a byproduct of the breakdown of red blood cells—in the baby’s blood when it isn’t excreted as it should be. When left untreated or if it is a severe case, jaundice can result in kernicterus, a condition that can lead to CP.
- Brain-based infection. If the child develops a brain-based infection such as bacterial meningitis or viral encephalitis, this could result in cerebral palsy. This type of infection could also set in if the baby does not receive his or her necessary vaccinations at the recommended times.
These Are Risk Factors, Not Absolutes
Although these are all risk factors that could potentially lead to a CP diagnosis, it’s important to remember that many mothers and babies experience these same issues and the baby never develops CP.
Therefore, these are simply factors that can raise the risk of CP, and are not absolutes.