Gestational age-specific neonatal mortality in Hong Kong: a population-based retrospective study

Background The neonatal period is the most vulnerable period during childhood, with the risk of death being the highest even in developed countries/regions. Hong Kong's neonatal mortality (1 parts per thousand) is among the world's lowest and has remained similar for 15 years. This study aimed to explore neonatal deaths in Hong Kong in detail and determine whether neonatal mortality is reducible at such a low level. Methods Live births in public hospitals in Hong Kong during 01 Jan 2006-31 Dec 2017 were included. Relevant data were extracted from the electronic medical records. Gestational age-specific mortality was calculated, and the trends were analyzed using the Cochran-Armitage trend test. Causes of death were summarized, and risk factors were identified in multivariate logistic regression analysis. Results In 490,034 live births, 755 cases (1.54 parts per thousand) died during the neonatal period, and 293 (0.6 parts per thousand) died during the post-neonatal period. The neonatal mortality remained similar overall (P = 0.17) and among infants born at 24-29 weeks' gestation (P = 0.4), while it decreased in those born at 23 (P = 0.04), 30-36 (P < 0.001) and >= 37 (P < 0.001) weeks' gestation. Neonates born at < 27 weeks' gestation accounted for a significantly increased proportion among cases who died (27.6% to 51.9%), with hemorrhagic conditions (24%) being the leading cause of death. Congenital anomalies were the leading cause of death in neonates born >= 27 weeks' gestation (52%), but its cause-specific mortality decreased (P = 0.002, 0.6 parts per thousand to 0.41 parts per thousand), with most of the decrease attributed to trisomy 13/18 and multiple anomalies. Conclusion Reduction of neonatal mortality in developed regions may heavily rely on improved quality of perinatal and neonatal care among extremely preterm infants.

Automated summary

This study provides a detailed analysis of neonatal deaths in Hong Kong, showing that overall neonatal mortality remains stable but varies among different gestational weeks. The proportion of extremely preterm infants who died significantly increased, with hemorrhagic conditions being the leading cause of death. Congenital anomalies were the leading cause of death in neonates born after 27 weeks' gestation, but their cause-specific mortality has decreased, mainly attributed to trisomy 13/18 and multiple anomalies.