Now researchers say experiments show that soft airy bedding, far from cutting the risk of suffocation, increases it if a baby is laid on its front.
There were 326 cot deaths in England and Wales in the first nine months of 1992, compared with 723 in the same period of 1991. Researchers at the University of Otago, New Zealand, found that carbon dioxide breathed out by a baby sleeping with its face close to the mattress builds up in the loose fibres of soft bedding.
Harder bedding, or a mattress covered in a rubber sheet, is far safer, they say in the current Archives of Disease in Childhood medical publication.
They conducted experiments using a mechanical dummy that simulated the breathing process of a three- month-old baby, laying it on its front on 12 commonly-used bedding materials.
On softer mattresses, within 90 seconds up to 10 per cent of the air the model breathed in was carbon dioxide. But when harder mattresses were used, or a rubber sheet placed between the mattress and the top sheet, the carbon dioxide was dispersed more quickly and far less was breathed in.Reuse content