Perinatal events associated with birth asphyxia and hypoxic-ischemic encephalopathy in a middle-income country: A multicenter, observational study.

Abstract

Background: Risk factors for neonatal encephalopathy differ across high- and low-income countries. Evidence of demographic characteristics and factors associated with perinatal hypoxia of infants who are at-risk for HIE in Southeast Asia is needed. Our primary objective was to investigate the intrapartum characteristics of infants ≥32 weeks’ gestational age (GA) born with low Apgar scores. Secondary objectives were to determine perinatal hypoxic events, and the characteristics and outcomes of infants ≥35 weeks GA with hypoxic-ischemic encephalopathy (HIE). Methods: A multicenter, retrospective, study was conducted. Individual charts were reviewed of infants with 5-minute Apgar scores ≤5 who were admitted to 4 tertiary centers in Thailand over 5 years. Events associated with perinatal hypoxia and outcomes were extracted. Variables were compared using chi-square, Fisher-exact test, two-independent sample t tests, ANOVA and Mann-Whitney. Data were analyzed using SPSS Statistics version 18.0. A p-value <0.05 was considered statistically significant.Results: Among 120235 infants, 454 had 5-mintue Apgar scores ≤5 (average: 3.8 per 1000 live births). The estimated frequency of HIE in ≥32 weeks’ GA infants was 1.5 per 1000 livebirths. Ninety-seven percent of the mothers’ received antenatal care. After exclusions, 316 infants and 314 mothers comprised the final sample. Common intrapartum complications were abnormal fetal heart rate (38.5%) and meconium-stained amniotic fluid (19.1%). Infants ≥35 weeks GA had mean ± standard deviation (SD) birthweight of 3003.4 ± 590.5 g; 10% were small-for-GA. Among ≥35 weeks GA infants with HIE, 42% had metabolic acidosis, 53% experienced sentinel, hypoxic perinatal events and advanced resuscitation was instituted in 92%. The severity of encephalopathy was reported in 99% of subjects. Eighty-five infants (62.5%) met all eligibility criteria for therapeutic hypothermia (TH) and 48 (56.5% of eligible infants) received treatment. The overall mortality rate was 29.4%.Conclusion: Maternal and intrapartum characteristics of infants at-risk for perinatal asphyxia in Thailand were comparable to reports from high-income countries. To improve recruitment for TH in middle-income, South-East Asian countries, strategies to raise HIE awareness among practitioners and more simplified TH eligible criteria are warranted to encourage timely transfer to referral centers for treatment.