Classic observations indicated that in the development of the intracranial hemorrhage (IH) of neonates fluctuations in arterial pressure, asphyxia, and coagulopathy can be involved. The mutation of factor V Leiden (LM) is associated with activated protein C resistance and ultimately with increased risk for thrombophilia. The relatively high incidence of the LM in the average population had prompted us to analyze the prevalence of the LM in neonates with IH.

We analyzed the DNA of 60 neonates having IH established by repeated ultrasonographies; results of 250 random patients at our NICU served as controls.

A segment of the factor V gene was amplified with PCR; the product was digested by Mnl I restriction endonuclease; and the digests were separated on agarose gels.

We found 9 patient with LM heterozygosity (15%), while this frequency was only 6.4% in the controls (p<0.05). This study first demonstrates that carriage of LM, probably in combination with other factors, or as an element of events mentioned above, can be regarded as a risk factor for the development IH in neonates.