Outcomes
Infant mortality was defined as death during the first year of life. Neonatal and postneonatal mortality were defined as infant deaths within and after the first 28 days of life, respectively. Causes of death were categorised into 11 groups according to ICD codes (appendix A of online data supplement): congenital anomalies, birth asphyxia, other neonatal morbidities (non-asphyxia), sudden infant death syndrome (SIDS), infections, cardiovascular and pulmonary causes, endocrine and metabolic disorders, neuromuscular disorders, malignant neoplasms, external causes of deaths, and other causes.