Epidemiology, etiologic factors, and prenatal diagnosis of open spinal dysraphism.

The caudal neural tube closes late in the first month after fertilization and failure of it results in myelomeningocele. Epidemiologic studies have shown differences in prevalence at birth based on ethnic-racial backgrounds and geography. Etiologic factors include the drug valproic acid or carbamazepine. Periconceptional folic acid supplementation appears to decrease the prevalence of neural tube defects. Numerous modalities allow for prenatal diagnosis of myelomeningocele. A cesarean section, before rupture of amniotic membranes and onset of labor, decreases the degree of paralysis.