The Timing of SIDS Deaths in Premature Infants in an Urban Population

Summary: Previous reports have demonstrated that premature infants are at greatly increased risk for sudden infant death syndrome (SIDS). Although only 9 % of infants are born at less than 36 weeks ’ gestation, 20 % of SIDS victims are former premature infants. The objective of this study was to characterize the time course of SIDS in premature infants and to determine why SIDS occurs at such a high rate in this patient population. A database of all cases of SIDS in Philadelphia from 1987 through 1991 was used to establish the time course for SIDS deaths in term and preterm infants. Gestational age was established by Dubowitz exam. To evaluate distinctly different age groups, infants from 32-36 weeks were excluded from analysis. Age at death and postconceptional age of death were compared for both groups. Data are described in weeks (mean ± SEM), and analyzed using unpaired t-test and log-rank test to compare survival rate between term and preterm infants. A significant difference (P<0.01) was noted in age at death of term versus preterm infants. No difference was found in postconceptional age of death. The survival rates were also different (P<0.001). Preterm infants showed a much wider distribution in age of death from SIDS. The term infants followed the classic SIDS curve. By 32 weeks ’ postnatal age, 95 % of all SIDS had taken place in the term group, but only 75 % in the preterm group. The age at death for SIDS differs in the preterm infant. These data reinforce the concept of prolonged vulnerability of preterm infants to SIDS. Survival of greater numbers of premature infants makes it increasingly important to focus efforts for SIDS prevention in this group for a longer period of time