Antenatal Causes of Cerebral Palsy and Adverse Pregnancy Outcomes: Investigating Associations Between Inherited Thrombophilia, Cytokine Polymorphisms and Viral Infections
Scientists continuously research the causes and risk factors associated with the development of cerebral palsy. Although they have uncovered significant information about what causes cerebral palsy over the last few decades, much remains unknown. One study in particular, by the University of Adelaide, investigated three potential antenatal (before birth) causes in connection with cerebral palsy and other adverse pregnancy outcomes. These causes were inherited thrombophilia, cytokine polymorphisms, and viral infections.Inherited Thrombophilia and Cerebral Palsy
Thrombophilia is the medical term for abnormal blood coagulation. It increases a patient's risk of blood clots developing in the blood vessels, or thrombosis. Thrombophilia can be an inherited medical condition, stemming from genetic and/or acquired factors. Inherited thrombophilia can give an infant a predisposition to blood clots, and potentially cause antenatal infant mortality and morbidity.
A number of studies have focused on the association between inherited thrombophilia and cerebral palsy. In 1998, researchers proposed that undiagnosed thrombophilia in the mother or baby could cause blood clots to interrupt blood circulation - subsequently causing adverse pregnancy outcomes. Another study found a possible association between cerebral palsy and a condition called placental infarcts, which can stem from thrombosis in the spiral artery.
Another possible connection between thrombophilia and cerebral palsy could lie in the possibility of stroke. Fetal or neonatal stroke is a major cause of cerebral palsy in term and near-term infants. Around 40 percent of cerebral palsy cases stem from vascular factors, including hemorrhaging and stroke. Thus, inherited thrombophilia could play a role in vascular problems connected to cerebral palsy.Cytokine Polymorphism Involvement in Cerebral Palsy
Cytokines are a type of protein found in the brain. They are a well-known potential cause of cerebral palsy - namely when a maternal infection causes inflammation that increases the number of cytokine proteins in the brain and blood of the baby. Inflammatory cytokines can cause brain damage that translates into the development of cerebral palsy.
Cytokine polymorphism refers to cytokine proteins occurring in several different forms or genetic variations. Researchers identified a direct relationship between the cytokine polymorphism tumor necrosis factor-a (TNF-A) and cerebral palsy, although the nature of the relationship remains unknown. They also connected TNF-A with four other adverse pregnancy outcomes, including preterm birth and fetal inflammatory response syndrome.
The University of Adelaide study also looked at four common thrombophilic polymorphisms in association with cerebral palsy. It found that these polymorphisms altered the coagulation of blood, predisposing the infant to thromboembolism, or blood vessel obstruction from thrombotic material. The study further suggested that blood clots in developing fetuses have a strong correlation with the development of cerebral palsy.Viral Infections and Cerebral Palsy
Finally, the study looked at the known and unknown associations between viral infections and cerebral palsy. It was the first thesis to use molecular techniques to look for direct evidence of viral infections as a cause of cerebral palsy and adverse pregnancy outcomes. The study focused on neurotropic viruses that could cross the placenta to cause fetal brain damage. It included herpes and enterovirus families.
Researchers found a direct association between viral infections (viral nucleic acids) and cerebral palsy, as well as to preterm birth. It found direct evidence of associations between specific viruses and the screening cards of newborns delivered preterm. Furthermore, it found a link between in utero infection and pregnancy-induced hypertensive disorders. In other words, the study managed to find more direct evidence establishing the association between viral infections and cerebral palsy.Conclusion
Based on the findings of the University of Adelaide study, inherited thrombophilia, cytokine polymorphisms, and viral infections all carry associations with cerebral palsy and other adverse pregnancy outcomes. These antenatal conditions, if diagnosed in a mother, could preclude a cerebral palsy diagnosis.
Furthermore, the study found that the combined existence of the Herpes group B virus and any cytokine polymorphism significantly increased the risk of developing cerebral palsy. Combinations of other viral infections and cytokine polymorphisms also increased the risk of cerebral palsy. The study concluded that, "cerebral palsy is undoubtedly a multifactorial disorder, with many different causes leading to its development."Can You Prevent Cerebral Palsy?
Studies like this one into associations between cerebral palsy development and antenatal causes serve to increase the understanding of what factors increase a child's risk of cerebral palsy. Despite advances in the medical field and a more in-depth understanding of what causes cerebral palsy, however, doctors still cannot always prevent this condition. Cerebral palsy may be preventable if it stems from birth injuries, but not always if its cause is congenital. Unfortunately, as many as 90 percent of cerebral palsy cases are congenital.
Physicians and parents can take steps to prevent acquired and congenital birth injuries. For example, if a couple is aware of a genetic predisposition to developing cerebral palsy (such as inherited thrombophilia or viral infections), that couple can decide whether to conceive naturally or to adopt. This is as close to prevention as some couples will be able to achieve. Parents can take heart, however, in the fact that researchers are hard at work developing further knowledge of the causes and preventions of cerebral palsy.