Gender-specific association of multiple risk factors with neonatal moderate or severe hypoxic ischemic encephalopathy: a cross-sectional study.

Background: Neonatal hypoxic ischemic encephalopathy (HIE) leads to different degrees of neurological sequelae. The incidence of HIE is relatively high, and the causal pathways leading to HIE are still controversial. This study aimed to investigate the risk factors associated with HIE comparing differences between genders.

Methods: A cross-sectional study of 196 neonates diagnosed with HIE was conducted. Based on the severity of clinical findings, HIE was classified as mild, moderate or severe. For mild HIE, the outcomes were relatively less severe, whereas moderate to severe HIE could suffer serious consequences, including death, cerebral palsy, epilepsy. T-test, chi-square test and logistic regression were used to analyze data.

Results: Among the 196 neonatal HIE, 39 (19.9%) had mild HIE,157 (80.1%) had moderate or severe HIE. The logistic regression analysis showed that gender was a specific stratified characteristic of moderate or severe HIE. In the male neonates group, emergency cesarean section, abnormal labor stage and amniotic fluid contamination were associated with an increased risk of moderate or severe HIE, where the adjusted odds ratios (ORs) were 4.378 (95% confidence intervals (CI):2.263-6.382), 2.827 (95% CI:1.743-5.196) and 2.653 (95%CI:1.645-3.972), respectively. As expected, a significant additive effect was found in the interactions between emergency cesarean section and abnormal labor stage, as well as between emergency cesarean section and amniotic fluid contamination, where the relative excess risk of interaction was 2.315(95%CI:1.573-3.652) and 1.896(95%CI: 1.337-3.861) respectively.

Conclusion: Emergency cesarean section, abnormal labor stage and amniotic fluid contamination were risk factors of moderate or severe HIE in neonates, and the associations were significantly correlated with male gender. Notably, coinciding incidences of emergency cesarean section with abnormal labor stage, or emergency cesarean section with amniotic fluid contamination were possibly synergistic in increasing the risk of moderate or severe HIE. These findings may assist clinicians in strengthening their awareness on risks affecting HIE and help reduce the incidence of moderate or severe HIE in clinical practice.