An Adelaide pathologist calls on mothers to let their babies sleep in their cribs and avoid couches as well as other soft surfaces.

In an editorial published in the Medical Journal of Australia (MJA), University of Adelaide forensic pathologist Professor Roger Byard said research confirmed adults sleeping beside a baby could increase risk of infant suffocation.

When infants die in their sleep, pathologists look into the possibility of sudden infant death syndrome (SIDS) along with suffocation.

Prof Byard said half of all infants found unexpectedly dead were sleeping beside an adult at the time, which means the babies may have died from suffocation and not sudden infant death syndrome (SIDS).

"Accidental suffocation appears to be a more likely mechanism of death than subtle processes leading to SIDS," the professor said.

While many parents believe that sleeping next to their baby is related to establishing a more solid bond between them, Prof Byard said the risks far outweighed any of the perceived gains.

Prof Byard also raised the issue on letting babies sleep on couches and other soft surfaces, as these are also high risk factors for shared-sleeping death.

He explained that adults do not necessarily have to be lying over an infant completely for respiration to be compromised. He said surfaces and the immediate surroundings of a sleeping baby should be free from anything or anyone that could reduce oxygen flow for the baby.

Parental obesity and fatigue are also among the risk factors, he said.

"Some infants are particularly vulnerable to the effects of compromised breathing and there is often no clinical predictor of this vulnerability," Prof Byard wrote in his column.

Meanwhile, Dr. William Sears, author of books 'The Baby Sleep Book' and 'SIDS: A Parent's Guide to Understanding and Preventing Sudden Infant Death Syndrome,' wrote in his column on parenting.com that co-sleeping, if practiced wisely and safely, can actually lower the risk of SIDS.

Dr. Sears mentioned a study by Dr. James McKenna, director of the Mother-Baby Sleep Laboratory and Professor of Anthropology at the University of Notre Dame, which showed that when mothers co sleep with their babies, they develop between them a "nighttime harmony," which means mom is more likely to subconsciously sense if her baby's health is in danger and wake up.