Causes and risk factors of cerebral palsy. CP during pregnancy.

Introduction

About 30 thousand people with cerebral palsy (CP) live in Ukraine now. Their abilities differ significantly: for example, some people can walk independently, while others need regular help with mobility. Due to the varied signs of the same disease, the parents of children with CP often try to find the answers to quite logical questions:

• Why didn’t my doctor offer me the diagnosis of cerebral palsy during pregnancy?
• What is the main reason for CP?
• Why does my baby look and behave in a completely different way than his/her peer with the same diagnosis?

Consequently, we have decided to prepare this article to answer these questions.

1. Causes: a history of cerebral palsy research
2. Causes of cerebral palsy during pregnancy
3. Risk factors for cerebral palsy during pregnancy
4. Is the diagnosis of cerebral palsy possible in pregnancy?
5. Causes of cerebral palsy during labor
6. Risk factors for cerebral palsy during labor
7. Causes of cerebral palsy after birth
8. Risk factors for cerebral palsy after birth
9. Is it possible to determine cerebral palsy during the first year of life?
10. Myths about the causes of cerebral palsy

Causes: a history of cerebral palsy research

For the first time, both cerebral palsy itself and its possible causes were described in 1843 by the British orthopedic surgeon John Little in his publication «On the Deformities of the Human Frame». He reported the manifestation of spastic diplegia (the form of cerebral palsy) in the infant. Little suggested that the cause lies in acute lack of oxygen and mechanical brain injury directly before or during labor. Since then, spastic diplegia came to be known as Little’s disease.

The term «cerebral palsy» appeared much later. In 1889, Canadian-born physician William Osler implemented it into use. He was convinced that the main cause of cerebral palsy is the child’s brain damage. The most cited psychiatrist in the world, Sigmund Freud, also made refinements to the understanding of the nature of CP. He was the first to suggest pregnancy as the most common period of cerebral palsy. As you know, his assumption was fully confirmed.

Over time, the problem of cerebral palsy began to draw the attention of an increasing number of scientists. New theories and hypotheses appeared. To systematize the theoretical basis, in the late 1950s «Little Club» appeared in London. Members of this Club created «Memorandum on terminology and classification of cerebral palsy». It was a real breakthrough in cerebral palsy research: from this moment, the scientists and clinicians could use the same terms in this area.

The nature of cerebral palsy remains to be not entirely clear nowadays. Researchers agree that all forms of CP are due to the lesion of the developing brain. Thus, there is a logical question: if the precondition is the same, why are the symptoms of this disorder so different? The thing is that cerebral palsy is the result of damage to the different regions of the child’s brain because of different causes.

For each period of cerebral palsy, we identified probable causes and risk factors for this disorder. Cause produces an effect or condition; that by which a morbid change or disease is brought about. (Farlex, 2012). A risk factor is any attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease (official definition of WHO).

It is worth noting that a risk factor does not ensure that the child will have cerebral palsy, but it makes it more likely. Therefore, they need special attention and regular examinations by qualified specialists. If necessary, they will help with diagnostics and the choice of the most effective treatment.

Risk factors for cerebral palsy during pregnancy

1. Rh incompatibility, blood type incompatibility
   When a mother and her fetus have incompatible blood types, it can lead to severe jaundice. Therefore, in case if a blood type incompatibility is found, the considerable attention should focus on this issue.
2. Multiple pregnancy
   Studies prove that the risk of cerebral palsy in multiples is about 12 times greater. If one twin died, the risk is nearly 108 times greater.
3. Maternal disorders
   Some maternal disorders increase the risk of cerebral palsy in children. These disorders include epilepsy, thyroid diseases, obesity, blood clotting disorders, hypertension, heart abnormalities, diabetes mellitus, anemia, and occupational diseases (e.g., when the expecting mother works with vibration).
4. Bad habits of the mother
   The direct correlation has already been found between smoking, drinking alcohol or drug use and the birth of children with cerebral palsy. The fact is that these substances are extremely toxic to both the expecting mothers and their babies. These toxins cause not only hypoxia but also can be a risk factor for birth defects of internal organs.
5. Environmental factors
   Indirectly, all things that surround a pregnant woman can also affect the baby’s health. These factors include socioeconomic conditions, health care quality, and ecological characteristics.

Is the diagnosis of cerebral palsy possible during pregnancy?

The parents often ask: «Can the doctors detect cerebral palsy during pregnancy?». Unfortunately, this is not always possible. However, scheduled medical examinations, special tests, and an ultrasound may indicate the fetal pathology. This will enable specialists to assess available risk factors during pregnancy and provide further recommendations.

Causes of cerebral palsy during labor

About 20 years ago, there was a popular theory that the main cause of cerebral palsy is a birth complication. Nevertheless, today it has been proven that the risk of CP during labor is only 10-20% (according to the report of the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics). The principal cause of cerebral palsy during labor is asphyxia – a severe deprivation of oxygen in the blood and tissues of the child. It is especially dangerous for the brain, which is sensitive even to a small deficit of oxygen. Asphyxia occurs due to some birth complications – e.g., placental abruption, or too long a delivery.

Risk factors for cerebral palsy during labor

1. Labor complications
   Labor complication means any issue during the birth that can lead to a risk to the health of the mother or the baby. The most dangerous complications are preterm birth (before 37 weeks of pregnancy), prolonged birth, eclampsia, uterine rupture, umbilical cord pathology (a nuchal cord, umbilical cord knots, umbilical cord entanglement), and placenta (for example, placental abruption).
2. Low or high birth weight
   Newborns with a low birth weight (less than 2500 grams) and high birth weight (over 4000 grams) have a higher risk of cerebral palsy. The bigger difference in weight compared to the normal means increases this risk.
3. Breech presentation
   The physiological intrauterine position for the fetus is the cephalic presentation. Any other types of position, especially the breech presentation, can affect and prolong the labor, leading to asphyxia.
4. Birth injuries
   Unfortunately, sometimes some damage or injuries happen during childbirth. It can be a risk factor for cerebral palsy. For example, a birth injury may occur if the vacuum extractor or the obstetrical forceps are misused.

Causes of cerebral palsy after birth

Even after birth, some circumstances may present a threat of cerebral palsy. According to statistics, it`s about 5-10% of all cases. Why does this happen?

1. Severe jaundice
   The cause of the yellowish tint to a newborn`s skin during the jaundice is an increased bilirubin level. In a situation when this level is higher several times than normal and jaundice is not treated adequately, bilirubin can cause irreparable harm to the developing brain. Most often, severe jaundice may lead to a dyskinetic cerebral palsy.
2. Acute cerebral circulatory disorders
   Usually, the underpinning for this cause is the disease or condition that is not always possible to be detected early (e.g., fetal brain arteriovenous malformation, heart or blood disease). In such a situation, the risk of cerebral palsy exists due to an intracerebral hemorrhage that can occur even spontaneously.
3. Brain injury
   A brain injury of the infant (e.g., while falling or car accident) can lead to the symptoms of cerebral palsy.
4. Neuroinfectious diseases
   Neuroinfectious diseases affect the nervous system, from the brain and spinal cord to the muscles and nerves. They can cause motor and intellectual delay and even the loss of previously acquired skills.

Risk factors for cerebral palsy after birth

1. Rh incompatibility, blood type incompatibility.
   In cases of Rh or ABO incompatibility (when the baby’s blood type is “different” from the mother’s), antibodies may form that destroy the newborn’s red blood cells and can trigger hemolytic disease with a sharp rise in bilirubin. If severe jaundice is not recognized and treated in time, toxic brain injury may occur (bilirubin encephalopathy/kernicterus), which can sometimes lead to persistent neurological impairments, including the dyskinetic form of cerebral palsy. Therefore, infants at risk of incompatibility require close monitoring from the first days of life and bilirubin level checks.
2. The absence of vaccination.
   Vaccination can prevent many infectious diseases (e.g., meningococcal disease, tuberculosis, poliomyelitis, measles) that can cause inflammation of the brain and its membranes.
3. Blood disorders
   Some blood disorders (such as thrombophilia or sickle cell anemia) can cause acute cerebrovascular damage, which may be even the first sign of the disorder.
4. Lack of child injury prevention
   Even an ordinary situation can cause a traumatic head injury, which is so dangerous for the developing brain. For instance, misuse of a baby car or leaving a child alone on a dressing table can lead to serious injury. It is worth noting that it is difficult to determine the exact cause of cerebral palsy, as well as the time of the onset of this disorder. The causes and risk factors mentioned above do not necessarily work separately, but their combination can lead to each clinical picture.

Is it possible to determine cerebral palsy during the first year of life?

Doctors often diagnose CP in children between 12 and 24 months. However, even if it is impossible to determine cerebral palsy before this time, the specialists can assess the risks of CP and begin the treatment when necessary. Don`t despair when your child has a risk of cerebral palsy. The earlier it is known that pathology may occur, the faster it is possible to take measures to improve the motor and intellectual development of the baby.