Neonatal hypoxic-ischemic encephalopathy in apparently low risk pregnancies: retrospective analysis of the last five years at the University of Bologna.

Objective: To provide recent figures on the occurrence of neonatal hypoxic-ischemic encephalopathy (NHIE) from a Teaching Hospital.

Study Design: A retrospective case-control study was conducted in a tertiary level university hospital with more than 3000 deliveries annually. Twenty-four cases of NHIE that occurred in apparently low-risk pregnancies were analysed and compared to a group of controls for the most common labor variables. Odds ratios (OR) and 95% confidence intervals (CI) were calculated.

Results: Of 15,371 apparently low-risk deliveries, 24 cases of NHIE were observed (0.16%), with perinatal death or cerebral palsy occurring in nine of these cases (0.06%). The following intra-partum variables were significantly more common in cases than in controls: stained amniotic fluid (OR: 7.50; 95% CI:1.77-31.79), maternal fever (none in the control group), abnormal CTG (OR: 253.0; 95% CI: 26.70-2397), persistent occiput posterior (OR: 15.67; 95% CI: 2.25-104.53) and operative delivery (OR: 3.98; 95% CI: 1.39-11.33).

Conclusion: The incidence of NHIE is considerably low in a Tertiary care Centre.