This NCMD thematic report, the fourth published by the NCMD programme, aims to quantify the number of sudden unexpected deaths of infants and children in England, the proportion of these deaths that remain unexplained following review by a Child Death Overview Panel (CDOP), and the demographics and characteristics of these children. It provides detailed analysis based on the unique data collected and held by the NCMD, as well as testimonies from the lived experience of families and comprehensive recommendations for policymakers and professionals to ensure positive change in the future.

Key findings in brief:

• Of all 6,503 infant and child deaths occurring between April 2019 and March 2021 in England, 30% (n=1,924) occurred suddenly and unexpectedly, and of these 64% (n=1,234) had no immediately apparent cause.

Infant deaths (under 1 year)

• There was a link between unexplained deaths of infants and deprivation. A significantly larger proportion of unexplained deaths were of infants living in the most deprived neighbourhoods (42%) than those in the least deprived neighbourhoods (8%).
• There was a strong link between sudden, unexpected infant deaths and sleeping arrangements. Where it was known, 98% (n=124/127) of unexplained deaths occurred when the infant was thought to be asleep, and of those, 52% (n=64/124) of deaths occurred while the sleeping surface was shared with an adult or older sibling. Of the 64 deaths where the sleeping surface was shared, for 60% this sharing was unplanned and at least 92% were in hazardous circumstances e.g., co-sleeping with an adult who had consumed alcohol or on a sofa. Of the 124 deaths that occurred during apparent sleep, at least 75% identified one or more of the following risk factors related to the sleeping arrangements: put down prone (face down) or side; hazardous co-sleeping; inappropriate sleeping surface when sleeping alone; inappropriate items in the bed.
• Unexplained deaths among infants were more common in males (64%) than females (36%), and were strongly associated with low birthweight, prematurity, multiple births, larger families, admission to a neonatal unit, maternal smoking during pregnancy, young maternal age, parental smoking and parental drug misuse.

Child deaths (1-17 years)

• Both explained and unexplained deaths in this age group were associated with a history of convulsions. Where data were available (n=30), there was a history of convulsions recorded in 27% of children whose deaths remained unexplained in this age group. This incidence was similar to children whose deaths went on to be explained.
• Sudden and unexpected child deaths in this age group were highest in the most deprived neighbourhoods.
• For sudden and unexpected deaths that occurred during 2020 and had been fully reviewed by a CDOP (n=204), 84% went on to be explained by other causes.
• There were at least 32 unexplained deaths in 2020 of children in this age group.

P.29 Alcohol or substance use/misuse - Alcohol or substance use/misuse was recorded as a modifiable factor in 34 (27%) deaths. This included both previous alcohol or substance use by a parent or carer, and alcohol or substance use by a parent or carer at the time the child died. Alcohol consumption is not a risk factor for SIDS if there is no co-sleeping. However, parents who have consumed alcohol should not co-sleep with their baby. The risk of SIDS is higher if the infant is co-sleeping with one or more adults who have consumed drugs or alcohol. This includes both illicit drugs and prescription drugs where there has been a recent change in dosage or medication.