Two or three cot deaths in a family should not automatically arouse suspicions of infanticide, say the authors of the largest study ever carried out of the unexplained deaths of babies in the UK.
The issue has been particularly controversial in recent years. Trupti Patel and Sally Clark were both cleared of killing their babies after courts refused to accept the expert testimony of the paediatrician Professor Sir Roy Meadow that more than one death was likely to be an unnatural event.
In his book ABC of Child Abuse, Prof Meadow wrote that "two is suspicious and three murder, unless proved otherwise... is a sensible working rule for anyone encountering these tragedies."
Research in the Lancet medical journal published today reveals that even three deaths in one family can occur by natural causes; while a small proportion of second and third deaths do turn out to be murder.
Robert Carpenter and colleagues from the London School of Hygiene and Tropical Medicine reviewed the deaths of babies under one year old in families that had already experienced a cot death and that were enrolled on a support programme that now covers over 90% of the country.
Of 6,373 babies who had been through the Care of Next Infant (Coni) programme by December 1999, 57 died. Nine of those deaths were inevitable, they report, and 48 were unexpected. Two families lost two children and 44 lost one. Of the 46 first Coni children, they say, 40 deaths were natural and the other six were probably homicides: five committed by one or both parents (two criminally convicted) and one by a babysitter. Of the two families where a total of three babies died, one family suffered three natural deaths and the other was a triple homicide, they say.
"Our data suggest that second deaths are not that rare and that the majority, 80-90%, are natural," says Prof Carpenter. "Families who have experienced three unexpected deaths also occur."
Prof Carpenter says the study will have included almost all the families in the country in which there have been two or three sudden, unexpected baby deaths in recent years. "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."
Two cases of baby deaths were reopened by the authorities after the researchers investigated, and were reclassified as deliberate killings. One of them involved one of the two families in which three babies died.
Prof Carpenter says: "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."
