Causes and risk factors of cerebral palsy. CP during pregnancy.
About 30 thousand people with cerebral palsy (CP) live in Ukraine now. Their abilities are significantly different: for example, some persons are able to walk independently, when others need regular help for moving. 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 my doctor didn`t offer me the diagnostics 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 in order 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 diagnostics 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 the birth
8. Risk factors for cerebral palsy after the 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 the possible causes of this disorder 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» has 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 of the world, Sigmund Freud also made refinements to the understanding of the nature of CP. He was the first to suggest the 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. In order 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 the 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 the symptoms of this disorder are 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 of qualified specialists. If necessary, they will help with diagnostics and the choice of the most effective treatment.
Causes of cerebral palsy during pregnancy
According to various studies, from 70% to 90% of all CP cases arises before the childbirth.
Possible causes of cerebral palsy include:
1. Maternal infections during pregnancy.
The study results show that maternal infections during pregnancy increase the risk of the brain damage. The serious danger is in asymptomatic infection (when the pregnant woman even doesn`t know that she is ill). Infectious disorders that can cause cerebral palsy in pregnancy are toxoplasmosis, rubella, cytomegalovirus, herpes simplex, syphilis, parvovirus, and other bacterial and viral disorders.
2. Genetic mutations.
Until quite recently, the crucial opinion was that genetic mutations are premises for only 1-2 % cerebral palsy cases. Nonetheless, in 2016 an Australian-led research group has found that at least 14 % of cerebral palsy cases are likely caused by genetic mutations.
3. Fetal hypoxia.
Hypoxia is a condition in which the body is deprived of oxygen supply at the tissue level. A child can suffer from the lack of oxygen because of a plenty of factors. The most significant risk of hypoxia exists during placental insufficiency. When this pathology happens, blood flow to the placenta is inadequate, and it can`t deliver nutrients (including oxygen) to the fetus properly. Hypoxia is dangerous due to the resulting cell death that can lead to serious brain damage.
4. Congenital brain anomalies.
The slightest movement occurs due to complicated work of the neural pathways. Therefore, brain anomalies and malformations of their «center», the brain, are often accompanied by motor deficit besides other possible symptoms. The studies also confirm that: people with cerebral palsy have the brain anomalies more frequently.
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 show that the risk of cerebral palsy in multiples is about12 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 health. These factors include socioeconomic conditions, health care quality, and ecologic characteristics.
Is the diagnostics of cerebral palsy possible in 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 ultrasound may indicate the fetal pathology. This will enable specialists to assess available risk factors while pregnancy and provide further recommendations.
Causes of cerebral palsy during labor
About 20 years ago, there was the most popular theory that the main cause of cerebral palsy is the birth complication. Nevertheless, today it has been proved 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 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 meanings 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 to the cerebral palsy. For example, a birth injury may occur if the vacuum extractor or the obstetrical forceps are misused.
Causes of cerebral palsy after the birth
Even after birth, some circumstances may present a threat of the 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 are not always possible to be detected early (e.g., fetal brain arteriovenous malformation, heart or blood disease). In such 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 the 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 the motor and intellectual delay and even the loss of previously acquired skills.
Risk factors for cerebral palsy after the birth
1. Rh incompatibility, blood type incompatibility (див. тут).
2. The absence of vaccination.
Vaccination can prevent many infectious diseases (e.g., meningococcal disease, tuberculosis, poliomyelitis, measles) that can cause the 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 the ordinary situation can cause traumatic head injury, which is so dangerous for the developing brain. For instance, misuse of the baby car or leaving a child alone on a dressing table can lead to the serious injury. It is worth noting that it is difficult to determine the exact cause of the 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?
The doctors often diagnose CP in children from 12 to 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 about the possible occurrence of pathology, the faster it is possible to take measures to improve the motor and intellectual development of the baby.
Myths about the causes of cerebral palsy
Finally, let`s consider a few myths about the causes of cerebral palsy.
Cerebral Palsy is a rare disorder. The parents who have kids with cerebral palsy may think that this is a rare disorder. However, cerebral palsy is the most popular cause of motor impairment that causes disability in children. Sometimes it is completely non-obviously that a person is diagnosed with cerebral palsy because it`s manifestations can be minimal.
If a baby with cerebral palsy was born, a high probability of a disease exists for a future child in this family. Cerebral Palsy is not a hereditary disorder. There is a probability of only 1% that children with cerebral palsy will have brothers or sisters with the same disorder in the future.
Vaccination is the cause of cerebral palsy. There is no clinical and experimental evidence of the correlation between vaccination and cerebral palsy. At the same time, infection, which can be prevented by the vaccination, is one of the causes of cerebral palsy.
Cerebral Palsy is contagious. Because of the important role of the microbes as the cause of cerebral palsy, the wrong opinion can be formed that CP is contagious. However, cerebral palsy is a non-infectious disorder.
Thank you for your attention. We hope that the information in this article was useful and wait for your suggestions about the next topic of our blog.