在由维生素K缺乏引起出血的病例中,有25～60%(平均34%)发生颅内出血。出血的原因是由维生素K 缺乏而引起凝血酶原复合物的缺乏。维生素K 缺乏的机制:尚有许多不明之处。一般认为由于新生儿体内维生素K 的贮存量少,加上肝脏功能未成熟,肠内正常菌群的建立又需数日才能完成,因此在生后头2～3天与维生素K 相关的凝血因子的水平最低而有发生出血的危险。过了这个时期,与维生素K 相关的凝血因子的水平缓慢增加,数周内达正 Intracranial hemorrhage occurred in 25-60% (34% on average) of cases of bleeding caused by vitamin K deficiency. The cause of bleeding is the lack of vitamin K caused by the lack of prothrombin complex. Mechanisms of vitamin K deficiency: There are many uncertainties. It is generally believed that due to the small amount of vitamin K stored in the newborn and the immature liver function, the establishment of normal intestinal flora may take several days to complete. Therefore, in the first 2 to 3 days after birth, vitamin K-related coagulation factors The lowest level and the risk of bleeding. After this period, the level of clotting factor associated with vitamin K slowly increases, reaching positive within a few weeks