Babies who are put to bed with a dummy in their mouth have a significantly lower risk of falling victim to cot death, according to research published today.

The benefits are greatest among babies who are considered to be at the highest risk of Sudden Infant Death Syndrome (SIDS), such as those whose mothers smoke or share a bed with them. Experts said parents should be encouraged to use dummies, although some campaign groups urged caution.

More than 300 babies, mostly under 12 months old, die every year from cot death in the UK and it remains the most common cause of infant mortality.

The death toll has fallen steeply since parents were advised to always put their baby to bed on their backs, but there is still much confusion about the causes of cot death, and the best ways of preventing it.

The study is published in the British Medical Journal. Researchers from the Kaiser Permanente research foundation in California interviewed the mothers of 185 babies who had died of SIDS and compared their experiences with 312 "control" parents, whose children were healthy.

When other risk factors - such as the age of the mother, socio-economic status and smoking habits - were taken into account, babies who slept with a dummy were 90 per cent less likely to be a victim of cot death, the researchers found.

The reduced risk was strongest when the baby was in what the researchers called "adverse sleep environments" which are already known to increase the danger of cot death - such as sleeping on their stomachs, or in the same bed as their parents, or with a mother who smoked.

The experts believe that dummies may help to prevent cot death by changing the configuration of the airway passage surrounding the nose and mouth in a way that can stop babies from suffocating in their sleep. Sucking on a dummy may also help to boost development of the upper airways.

Dr De-Kun Li, senior research scientist at the foundation and author of the study, said: "Use of a dummy seems to reduce the risk of SIDS and possibly reduces the influence of known risk factors in the sleep environment. It is important that these findings be confirmed as they provide new insight into the underlying mechanisms of the protective effect of dummies."

Dr Li said that dummy use among higher risk babies was comparable with those in the low risk groups in his study.

He concluded: "Advocating the use of dummies for infants in high risk populations may have the potential to further reduce the incidence of SIDS."

While the number of cot deaths has fallen by 75 per cent since a high-profile Government awareness campaign was launched in 1991, the children of young single mothers and those from poorer families have a much greater chance of falling victim to the syndrome. Despite the wealth of research surrounding cot death, many parents are still unsure about the best ways of preventing it.

A recent survey by the Foundation for the Study of Infant Deaths (FSID) found that a third of new parents had not received any information about prevention.

A spokesman for the FSID said: "The current study appears to be convincing that the use of a dummy reduces the risk of cot death.

"But the statistical analysis is very complicated and needs careful study.

"There is no reason for parents not to use a dummy, but if they do, they must use it every time the baby sleeps, and never forget to give the baby the dummy. " he said.


* Lay your baby down to sleep on its back

Cot deaths have fallen by 75 per cent since a 1991 campaign telling parents to always put their babies to sleep on their backs, as leaving them on their fronts could lead to them suffocating. But research published last year said that babies who never sleep on their stomach may not learn the natural survival instincts that make them move their heads when lying prone. Nevertheless, researchers said that parents should continue to lie babies on their backs.

* Keep your baby lightly tucked up

Early research suggested that cot death may occur when babies are too tightly tucked up. But new theories are emerging that the age-old practice of swaddling babies may actually help to reduce cot death as the tight wrapping stops them from rolling on to their fronts and reduces stress levels by reminding them of the womb.

* Sharing a bed with your baby

Claims were made in the 1990s that babies who slept in the same bed as their parents were less stressed and less likely to fall victim to cot death. Now experts are strongly opposed to 'co-sleeping,' warning that parents risk rolling on to their babies, and that the children of smokers are at particularly high risk of cot death if they share a bed.