Sharing a bed with a very young baby significantly increases the risk of cot death, a study confirmed yesterday.
The danger is particularly high if the infant is sleeping between parents, whether or not the adults smoke or the mother breastfeeds her baby.
The survey, the second in 18 months to highlight the risks of bed sharing, led charities to reinforce government advice that the safest place for babies to sleep in the first six months of life is in a cot in their parents' bedroom.
Risks for babies under 11 weeks old were revealed in a study by Glasgow University and Ecob Consulting, which studied the circumstances surrounding the deaths of 123 babies in Scotland between 1996 and 2000.
It found that more than half of them, 64, had shared a bed, couch, chair or cot for their last sleep before death.
Of 46 infants who shared a bed at some stage of their last sleep, 40 were found dead in their parents' bed.
The proportion of bed-sharing babies among the dead was much greater than that among local babies in general: only about one-fifth, 53 of 263, of babies born at the same maternity units during the same period shared a bed.
The study, published in the US Journal of Paediatrics, was funded by the Scottish Cot Death Trust, whose chairman, James McClure, said: "Until recently it was thought that bed-sharing was a risk only if parents were smokers. This new study confirms a significant risk for young babies, whether or not parents smoke.
"Our advice is that while it's fine to have your baby in bed to feed or cuddle, you should put the baby back in his or her own cot or crib in your room before you go back to sleep. This is particularly important in the first three months of life, as the risk diminishes sharply after that age."
A Europe-wide study published in the Lancet last year found a similar risk for babies under eight weeks.
The Scottish study suggested that sleeping in a separate room only heightened the risk of a baby's death if a parent smoked, contrary to other statistical analysis that had suggested merely being in another room increased risk.
Joyce Epstein, director of the Foundation for the Study of Infant Deaths, said: "Health professionals [should] discuss safer sleeping for babies with every new parent, offering the live-saving message that the safest place for baby to sleep is in a cot in the parents' room for the first six months."
She said health professionals had resisted passing on the message because of the campaign to encourage breastfeeding. The foundation is funding research to establish why sleeping in a separate room might be less safe.
"Some people think ... parents and babies synchronise breathing and that might help the baby. Nobody knows why this is the case."
