Prematurity and sudden infant death syndrome: United States 2005-2007

In 1987, the sudden infant death syndrome (SIDS) rate in the United States was 1.2 per 1000 live births. By the year 2005, the SIDS rate had dropped more than half to approximately 0.5 per 1000 live births. In 1987, the risk of SIDS was 2.32 times greater for extremely premature infants compared with term infants. The objective of this analysis was to determine if with the falling SIDS rate there has been a change in the risk for SIDS among preterm infants.

Data were obtained from the United States Linked Infant Birth and Death Certificate Public User Period files for the years 2005 to 2007. The adjusted odds ratios (ORs) for postneonatal out-of-hospital death by gestational age were determined by logistic regression modeling.

Over the 3-year period, there were 5203 postneonatal out-of-hospital deaths attributable to SIDS; 2010 attributable to other sudden deaths; 1270 attributable to suffocation in bed; and 3681 attributable to other causes. The adjusted OR for SIDS among the most preterm infants (24 to 28 weeks gestation) was significantly increased compared with term infants, OR(adj)=2.57 (95% confidence interval=2.08, 3.17), as were the adjusted ORs for the other causes of sudden infant death.

Despite the marked drop in the incidence of SIDS since 1987, the risk for SIDS among preterm infants remains elevated. Other causes of sudden infant death for which SIDS is often mistaken reflect similar levels of increased risk among preterm infants.