Sudden unexpected infant death rate declines with higher gestational age
The rates of sudden unexpected infant death (SUID), which includes sudden infant death syndrome (SIDS) and other sleep-related infant deaths appear to be inversely associated with gestational age (GA), according to a recent US study.
Among 7,057,122 infant births and deaths between 2012 and 2013 recorded in the National Center for Health Statistics, 4,658 deaths were attributed to SUID (mean age 111.4 days). Besides SIDS, other sleep-related infant deaths contributing to SUID include ill-defined and unspecified causes of mortality (IUCM) and accidental suffocation and strangulation in bed (ASSB). Of the total SUID cases, 50 percent was due to SIDS (n=2,337, mean age 110.2 days), 27 percent was due to IUCM (n=1,268, mean age 113.0 days), and 23 percent was due to ASSB (n=1,053, mean age 112.1 days). [Pediatrics 2017;140:e20163334]
Compared with infants born at term (39–42 weeks’ GA), infants born at a lower GA (24–27 weeks) had higher postneonatal out-of-hospital death rates per 1,000 live births (2.68 vs 0.51 for SUID, 1.03 vs 0.26 for SIDS, 1.06 vs 0.13 for IUCM, and 0.60 vs 0.12 for ASSB).
After adjusting for potential confounders, the risk for SUID remained significantly higher in infants born at 24–27 weeks’ GA (adjusted odds ratio [adjOR], 3.55, 95 percent confidence interval [CI], 2.70–4.66; p<0.001) and even in infants born at 37–38 weeks’ GA (adjOR, 1.34, 95 percent CI, 1.23–1.45; p<0.001) compared with infants born at term.
Previous studies have shown that premature infants were more likely to be placed in a prone position and to bed-share on an adult bed after hospital discharge, which were found to be major risk factors for SIDS. [J Perinatol 2015;35:880-884] However, given the incomplete information in the gathered records, the role of infant sleep practices was not thoroughly evaluated in the current study, according to the researchers.
“[O]ur findings indicate that [the 2011 AAP*] enhanced recommendations for safe sleep education in the NICU** were not sufficient to reduce or eliminate the inverse association between GA and SUID or its component causes of death,” said the researchers, who called for further investigation on sleep practices and exposure to multiple risk factors which may elucidate the association between GA and SUID.
“The risk for SUID associated with prematurity likely has multiple aetiologies requiring continued investigation, including increased biological vulnerabilities to risk factors at earlier GAs and the efficacy of NICU education programmes,” said the researchers.
*AAP: American Academy of Pediatrics**NICU: Neonatal intensive care unit