Autopsy findings of co-sleeping-associated sudden unexpected deaths in infancy: Relationship between pathological features and asphyxial mode of death

Aim: Co‐sleeping is associated with increased risk of sudden unexpected death in infancy (SUDI)/sudden infant death syndrome (SIDS). The aim of this study is to examine autopsy findings from a single UK specialist centre to determine the relationship between co‐sleeping and cause of death. Methods: Retrospective analysis of >1500 paediatric autopsies carried out by paediatric pathologists over a 10‐year period. SUDI was defined as sudden unexpected death of an infant aged 7–365 days; deaths were categorised into explained SUDI (cause of death was determined) and unexplained SUDI (equivalent to SIDS). Results: There were 546 SUDI; sleeping arrangements were specifically recorded in 314; of these, 174 (55%) were co‐sleeping‐associated deaths. Almost two thirds (59%) of unexplained SUDI were co‐sleeping compared to 44% explained SUDI (95% confidence interval (CI) 1.0–27.2%, P= 0.03); however, this difference remained statistically significant only for the first 5 months of life (95% CI 3.5–33.2%, P= 0.01). In unexplained SUDI aged < 6 months, there were no significant differences between co‐sleeping and non‐co‐sleeping deaths with respect to ante‐mortem symptoms, intrathoracic petechiae, macroscopic lung appearances, pulmonary haemosiderin‐laden macrophages, and isolation of specific bacterial pathogens; however, fresh intra‐alveolar haemorrhage was reported more commonly in co‐sleeping (54%) than in those that were not (38%; 95% CI 1.4–30.5%, P= 0.03). Conclusions: Co‐sleeping is associated with unexplained SUDI/SIDS in infants aged < 6 months, suggesting that co‐sleeping is related to the pathogenesis of death in younger infants. The finding that intra‐alveolar haemorrhage is more common in co‐sleeping suggests that a minority of co‐sleeping‐associated deaths may be related to an asphyxial process.