Demographic and clinical characteristics of study population
| Characteristics | Cases (n=223) |
| Male gender, n (%) | 134 (60.1) |
| Birth weight, median (quartiles) | 2640 (1640–3200) |
| Gestational age*, median (quartiles) | 35 (31–39) |
| Age at diagnosis (days), median (quartiles) | 2 (0–18) |
| Age at death (days), median (quartiles) | 13 (3–42.5) |
| Proportion of caesarean section delivery (%) | 142/218 (65.1) |
| Proportion of abnormal MRI results (%) | 34/37 (91.9) |
| Proportion of abnormal EEG results (%) | 29/35 (82.9) |
| Ultrasonic cardiogram | |
| Normal (%) | 5/198 (2.5) |
| PDA/PFO/ASD/PAH (%) | 132/198 (66.7) |
| Arrhythmia | 3/198 (1.5) |
| Complex malformation† | 41/198 (20.7) |
| Cardiac insufficiency | 17/198 (8.6) |
*Sixteen term infants missed the exact gestational age were not calculated.
†Complex malformation included pericardial effusion, ventricular septal defect, coarctation of the aorta and other functional defects.
ASD, atrial septal defect; PAH, pulmonary artery hypertension; PDA, patent ductus arteriosus; PFO, patent foramen ovale.