In three newborns already during the fetal period hydrocephalus intern
us had been diagnosed by ultrasound later found to be due to sinus ven
ous thrombosis. After birth two of these newborns had no remarkable ne
urological signs, the third had seizures, All of them had hydrocephalu
s internus, intracerebral hemorrhage, and non or reduced doppler ultra
sound flow within the venous sinus, Etiopathology is discussed with re
ference to the literature: damage of the endothelium, venous stasis, h
yperviscosity, hypercoagulation slate, protein C-, S- and antithrombin
III-deficiencies, trauma.