1, prematurity Premature infants, especially those with a gestational age of less than 32 weeks, have immature capillary networks in specific parts of the brain and are prone to bleeding due to hemodynamic changes. after 32 weeks this tissue becomes gradually mature. Xi’an Children’s Hospital Pediatric Neurosurgery Shi Yongqiang 2. Hypoxemia during ischemic-hypoxic asphyxia, hypercapnia The autoregulation of cerebral blood flow can be impaired, forming a pressure passive cerebral blood flow. Can bleed due to increased cerebral blood flow, capillary rupture; can also be reduced blood flow, capillary ischemic injury and bleeding. 3, trauma mainly for birth injuries, such as fetal malposition, fetal oversize and other fetal head excessive pressure, or the use of forceps, fetal head suction, breech traction and other mechanical injuries 4, other neonatal liver function immaturity, coagulation factor deficiency or suffer from other bleeding disorders, such as maternal use of sodium phenytoin, rifampin, phenobarbital and other drugs during pregnancy can cause neonatal platelet or coagulation factor reduction; inappropriate input of sodium bicarbonate Hypertonic solutions such as sodium bicarbonate can also lead to capillary rupture.