The risk of sudden death is greatly increased for young babies if they share a bed with their parents, a coroner has found.
But South Australian Coroner Mark Johns said young babies could benefit from sleeping in the same room with their mother and father, the extra stimulation reducing the risk of Sudden Infant Death Syndrome (SIDS).
The coroner's findings followed an inquest into the deaths of five young babies in South Australia between July 2007 and November 2008.
The youngest was aged just three weeks and the oldest 10 months.
While the cause of death remained undetermined in four of the cases, the infants were all sharing a bed or were sleeping with an adult when they died.
In one case an autopsy concluded a month-old baby girl had suffocated after becoming trapped between the cushion and the back of a couch after falling asleep with her father.
"The message to be drawn from these five tragic deaths is that the risk of sudden, unexplained death in infancy is greatly increased where a child sleeps in the same bed with one or more parents or other adults, whether the mechanism of death is asphyxia due to overlaying, bedding or otherwise," Mr Johns said.
"On the other hand, there are benefits to parents sharing a room with an infant where the infant is sleeping in a safe cot expressly designed for that purpose."
In evidence to the inquest, forensic pathologist Roger Byard said western culture had turned co-sleeping into something dangerous.
He said in some cultures babies traditionally slept with their parents, but usually on firm bedding or the floor and without the weight of heavy coverings.
In the west adults were sharing soft, high beds with young babies and covering themselves with doonas or blankets.
"What we've done in the west is we've made co-sleeping dangerous," he said.
Prof Byard said small infants, aged under six months, were particularly at risk when bed sharing.
Because of their age they were unable to rescue themselves from a dangerous situation, such as if their nose and mouth were covered, he said.
Prof Byard said there were advantages to co-sleeping, including enhanced bonding between parent and child and assistance with breastfeeding and settling.
But he said the best approach was to have a baby sleep in a well constructed cot with a firm mattress and for the cot to be placed in the parents' bedroom.