Repeated unexpected infant deaths most likely to be from natural causes

December 30, 2004

The most comprehensive epidemiological study to date into recurring sudden unexplained infant death syndrome (SIDS) is published in this week's issue of THE LANCET. Authors of the study conclude that natural causes can explain the deaths of a second or even third unexpected infant death occurring in the same family.

There have been suggestions that when two or three unexpected unexplained infant deaths occur within a family they are more likely to be unnatural than natural. Robert Carpenter (London School of Hygiene and Tropical Medicine, London, UK) and colleagues assessed the proportion of natural and unnatural infant deaths (ie, deaths before the age of 1 year), occurring in families enrolled on a support programme for parents who had previously experienced SIDS.

The Care of Next Infant programme (CONI) supports parents who have experienced SIDS and is currently available in over 90% of health districts in England, Wales, and Northern Ireland. The investigators studied all deaths in 6373 infants who had completed the CONI programme by December, 1999. After a CONI death, detailed enquiries were made into the previous death and the CONI death, including a family interview, a review of autopsies, and case discussion.

57 (8.9 per 1000) CONI infants died. Nine deaths were inevitable, and 48 were unexpected. 44 families lost one child, and two families lost two children. Of the 46 first CONI deaths, 40 were natural; the other six were probable homicides, five committed by one or both parents (two criminally convicted). Enquiries identified 18 families with two SIDS deaths and two families with probable covert double homicides.

Professor Carpenter comments: "Our data suggest that second deaths are not rare and that the majority, 80-90%, are natural. Families who have experienced three unexpected deaths also occur. The study included two families in which there were two CONI deaths--one triple SIDS and one triple filicide."

He adds: "This study is the largest follow-up of families who have had a sudden unexpected and unexplained infant death. The CONI programme has been available in over 75 % of districts in England, Wales, and Northern Ireland since 1994, and we would know if many eligible mothers declined to participate. We have therefore probably included the majority of families in which there have been two or three sudden and unexpected deaths in recent years. Consequently, although child abuse is not uncommon, from the best available data, we believe that the occurrence of a second or third sudden unexpected death in infancy within a family, although relatively rare, is in most cases from natural causes. For a host of reasons, not the least of which is the protection of parents from false accusations, it is essential that all sudden unexpected infant deaths are submitted to a detailed, expert investigation like this study, which includes a full family history, clinical history, and paediatric autopsy."

In an accompanying commentary (p 3), Tom Matthews (University College Dublin, Ireland), states: "Carpenter and colleagues document the difficulties in categorising some unexpected deaths, with deaths labelled as infanticide only if supported by unambiguous evidence. Their main conclusion is that the recurrence rate of unexpected deaths or SIDS is about 6 per 1000 and that most of these second deaths are from natural causes. So the mere occurrence of a second death is, in itself, insufficient to justify the label of infanticide. Although some families with an unexpected death have worryingly disorganised parenting skills and support structures, Carpenter and colleagues show that unexpected deaths recur, which implies that a diagnosis of infanticide should require more definite evidence."
Contact: (Wed 29 December to 1300 H UK time fri 31 December only) Professor Robert Carpenter, Medical Statistics Unit, Department of Epidemiology & Public Health, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK; T) (mobile only) 44-1-689-811-153;

Professor Tom Matthews, Department of Paediatrics, University College Dublin, Children's University Hospital; and Rotunda Hospital, Dublin 1, Ireland; T) 353-1-878-4344;


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