Babies who co-sleep with their parents are five times more likely to die from Sudden Infant Death Syndrome, according to a new study. A British Medical Journal Open study reveals that the risk for SIDS or cot death increases when babies sleep on the same beds with their parents.

The risk is also higher for babies less than three months old who co-sleep with their parents even when neither parents smoked, drink, or take drugs.

"Our findings suggest that professionals and the literature should take a more definite stand against bed sharing, especially for babies under 3 months," the authors of the research has been quoted by the Herald Sun as saying.

"If parents were made aware of the risks of sleeping with their baby, and room sharing were promoted, as 'Back to Sleep' was promoted 20 years ago, a substantial further reduction in SIDS rates could be achieved."

The study included data on 1472 SIDS cases and 4679 controls, and included cases from Australia. It also found out that around 50 per cent of SIDS cases occur when babies share beds with their parents.

The high rate of SIDS due to bed-sharing can be attributed to bacteria that reside in the parents' bed, according to University of Adelaide paediatrician.

"A baby sleeping in such a contaminated environment could inhale or ingest shed skin cells covered in these bacteria. A genetically susceptible baby is at risk in the co-sleeping situation. This risk is further increased with every additional risk factor," he said.

Dr Mark Kohler, lecturer at the Centre for Sleep Research in University of South Australia, added that bed-sharing increases the likelihood of "increased exposure to toxins" and smothering infants in some way.

The study should especially raise alarm in Australia because only parents who smoke, drink, or take drugs are advised to avoid sleeping with their baby, according to the paper.