[Prenatal diagnosis of severe neural tube defect in negative biochemical findings].

With reference to a case of occipital encephalocele associated with iniencephaly diagnosed by ultrasonography in the 20th week of pregnancy, the diagnostic problems of craniospinal defects, factors influencing prognosis and clinical consequences are described. Even when results of biochemical tests are negative, minute neural canal defects can be diagnosed early by ultrasonography. In the authors' opinion an ultrasonographic diagnosis of encephalocele represents an indication for termination of pregnancy, in view of the poor prognosis.