Six to eight percent of all newborns are born prematurely. Preterm delivery remains the most severe event regarding morbidity and mortality of the premature infants. The most serious complications in the treatment of prematurity are intracerebral bleedings that lead to progressive hydrocephalus and neurological handicaps in those newborns who survive. To our knowledge, about 50% of premature births with cerebral bleedings of stage I-II show normal or slightly decreased postnatal development. Both, a sufficient oxygen utilisation and a regulation of cerebral blood perfusion are necessary to prevent periventricular leucomalacia and cerebral bleedings with impairment of parenchymatous tissue. Endothelial swellings with decreasing blood flow into the cerebral parenchyma were found only in cases of prolonged oxygen deficiency. Vasoconstriction may produce a circulus vitiosus. However, it is important to know that more than 50% of the premature infants probably suffer from initial cerebral bleedings already in the prenatal stage. During the last 10 years the infectious pathogenesis has resulted in better understanding of pathophysiologic factors for prematurity. The local cervical activation of interleukins (IL 1, 6, 8) caused by cervical infections stimulate the prostaglandin synthesis and cervical maturity.