The hypothesis is that a high rate of the complex t-PA-PAI-1 in cord blood could be a high risk of intracranial hemorrhage in preterm infants and provide predictive of their occurrence. The rates of MMP-3, PDGF-C and PAI-1 free in cord blood, and the polymorphism of PAI-1 gene and eNOS could separately or associated with the main criterion to identify predictive of hemorrhages.