Viral Infection in Pregnancy and Congenital CNS Malformations in Man

THE association between congenital central nervous system (CNS) developmental anomalies and viral infection occurring in pregnancy has been definitely shown in man with rubella virus1-4 and cytomegalovirus.5-9 Microcephaly, hydrocephaly, anencephaly, encephalomyelocele, meningomyelocele, and Dandy-Walker syndrome with obstructive hydrocephalus, have all been described in congenital rubella. The CNS involvement may also be in the form of an encephalomyelitis, and mental retardation is common. Like rubella, human cytomegalovirus can induce significant CNS pathology. This may take the form of a meningoencephalitis, microcephaly, hydrocephaly, microgyria, porencephaly, or periventricular calcifications. Mental retardation, seizures, and other signs of focal cerebral dysfunction are neurological features of survivors of congenital cytomegalic inclusion disease. Other viruses such as mumps,10,11 herpes simplex,12-15 rubeola16 and influenza17,18 have been linked with human congenital abnormalities, not specifically of the central nervous system. Evidence of causal relation, however, between these viruses and the congenital abnormalities is tenuous.