Trends and Causes of Neonatal Mortality in Canadian Neonatal Intensive Care Units

To determine patterns and causes of neonatal deaths in Canadian neonatal intensive care units (NICUs) over the last decade.

All neonatal deaths reported by NICUs participating in the Canadian Neonatal Network 2010-2022 were divided retrospectively into 2 groups by gestational age (GA), <33 weeks and ≥33 weeks. Cause of death was assigned using prespecified classification criteria adapted from published criteria. Demographic, perinatal, and neonatal characteristics of newborns who died were compared with those of the survivors. Trends in birth characteristics and causes of death over 3 epochs (2010-2013, 2014-2017, and 2018-2022) were evaluated.

A total of 5646 (2.96%) newborns died after receiving intensive care; 3782 (67%) were born at <33 weeks and 1864 (33%) at ≥33 weeks GA. The most common cause of death at <33 GA weeks was extreme prematurity (<28 weeks), followed by respiratory causes. Among those with GA ≥33 weeks, the leading cause of death was central nervous system conditions, followed by congenital anomalies and malformations. Most deaths occurred between days 2-7, followed by days 8-28 after birth. Over the 3 epochs studied, deaths associated with extreme preterm birth decreased significantly, but other causes of death remained unchanged.

In Canadian NICUs, among infants with GA <33 weeks, extreme preterm birth was the leading cause of mortality. Central nervous system-related conditions were the predominant cause of death in infants born ≥33 weeks. Deaths due to extreme preterm birth decreased over the last decade in Canada, likely reflecting increased provision of active resuscitative care.