Background There have been dramatic improvements in survival for preterm infants over the last two decades that is likely to result in a changing prevalence of the major neonatal morbidities. It is important to accurately document these changes, and identify current patterns, in order to inform research and development priorities.
Objective To ascertain the major causes of death in preterm infants using a population based database, and to determine any changes over the last two decades.
Design/Methods The authors used the Perinatal Mortality Survey—a large population based database to obtain information on all infant deaths among those live born between 24 and 31 weeks gestation between 1988 and 2008. Clinico-pathological diagnoses for the major morbidities were hyaline membrane disease, pulmonary immaturity (immaturity making sustained ventilatory support impossible), malformations (genetic or structural), infection (including ante-, intra-, and postpartum) and necrotising enterocolitis (NEC). Infants were subdivided into those born extremely (24–27 weeks) and very (28–31 weeks) preterm, and into three 7-year cohorts 1988–1994, 1995–2001 and 2002–2008.
Results There were 1504 deaths in live born preterm infants <32 weeks gestation with median gestation 26 weeks (IQR 3w), median birth weight 880 g (IQR 469g) and median age at death 3 days (IQR 14 days). There was a major decrease in respiratory deaths especially in those born at 28–31 weeks, and a significant increase in the relative importance of deaths from NEC and infection especially in those born at 24–27 weeks.
Conclusion This is one of the largest published population based case series of mortality in preterm infants. This shows a large overall decrease in deaths in infants born preterm, differential trends between extremely and very preterm infants, and the increasing importance of deaths due to NEC and infection.