[Birth asphyxia, neonatal risk factors for hypoxic ischemic encephalopathy]

Neonates suffering from severe birth asphyxia may develop hypoxic ischemic encephalopathy (HIE), some of which develop permanent neurological damage. As the incidence of asphyxia and HIE in Iceland is unknown, this study was conducted. Furthermore, we evaluated the association between some neonatal risk factors and the development of HIE.

All term infants born at LSH from 1997-2001 with birth asphyxia, defined as 5 minute Apgar score or=<6, were included in the study. Clinical information, length and weight, Apgar scores at 1, 5 and 10 minutes normoblasts count, initial pH and hemoglobin levels were retrospectively collected.

The incidence of HIE after birth asphyxia was 1.4/1000. The infants who developed HIE had significantly lower birth weight and Apgar scores at one, five and ten minutes. They also had lower umbilical artery pH, had more base deficit and lower serum bicarbonate concentrations than the infants who did not develop HIE.

The incidence of HIE was low compared to other studies. Birth asphyxia resulting in HIE is associated with lower birth weight, Apgar scores, pH and neonatal hemoglobin levels at birth. We conclude that neonates with low hemoglobin level are at increased risk for developing HIE and that low pH and Apgar scores may predict worse outcomes after birth asphyxia.