Risk Factors for Hypoxic-Ischemic Encephalopathy in Asphyxiated Newborn Infants
Sitthivuddhi Futrakul MD, MSc*, Pramote Praisuwanna MD*, Pimolrat Thaitumyanon MD*
Affiliation : * Neonatal Unit, Department of Pediatrics, King Chulalongkorn Memorial Hospital, Chulalongkorn University
Objective : To determine the risk factors for hypoxic-ischemic encephalopathy (HIE) in asphyxiated newborn
infants.
Materials and Methods : A retrospective study of 17,706 newborns, who were admitted to the Neonatal Unit of
King Chulalongkorn Memorial Hospital, from July 1999 till the end of December 2000. 84 infants with
perinatal asphyxia were enrolled in the present study. All of the possible risk factors that might have contrib-
uted to asphyxia were identified and recorded. HIE was diagnosed based on the Modified Sarnat-Sarnat
Score for the diagnosis of neonatal encephalopathy. The clinical data of the HIE group were compared with
those of the HIE negative group. The categorical data were analyzed for statistical significance (p < 0.05) by
Chi-square test or Fisher exact test, or Student t-test. The odds ratio and 95% CI were calculated for those with
statistical significance. Stepwise multiple logistic regression analysis used to determine the independent
factors that may predispose an infant to HIE.
Results : Inappropriate antenatal care (OR 9.4; 95%CI: 2.6-35.4), post-term gestation (OR 7.4; 95%CI: 1.4-
34.8), vacuum extraction (OR 5.4; 95%CI: 1.1-26.8), male (OR 4.8; 95%CI: 1.3-19.1), prolapsed cord (p =
0.01) and 1 and 5-minute Apgar scores, (p < 0.0001) were significant risk factors for HIE. However, by
multiple regression analysis, only a 5-minute Apgar score was significantly associated with HIE (p = 0.001).
Conclusion : Sophisticated or expensive equipment is not necessary for the treatment of HIE patient. HIE
depends mainly on adequate and effective supportive strategy. The delivery of high risk pregnancies, under
obstetric facilities and with appropriate intervention and with good neonatal resuscitation, may prevent the
perinatal asphyxia and thereby minimize the occurring of HIE.
Keywords : Risk factors, Perinatal asphyxia, Hypoxic-ischemic encephalopathy
