London - Thousands of parents may be putting their babies in danger by nodding off with them on a couch or armchair.
Sleeping this way can raise a baby’s risk of sudden infant death syndrome 50 times.
But a survey has found that two in five parents have done so – and a quarter have done it more than once.
Parents are advised to put babies to sleep in a bed or cot because a firm mattress allows heat to escape from the backs of their heads. When a baby’s head sinks into a soft chair, the heat cannot escape so well, raising the risk of overheating.
Some experts believe this is one of the causes of sudden infant death syndrome, known as SIDS – the unexpected and unexplained death of an apparently healthy baby.
Babies sleeping on a sofa or chair can also become trapped and suffocate.
Parents can safely co-sleep with children in some situations but the Lullaby Trust charity, which carried out the survey, has warned doing so on a sofa or chair, or after drinking or smoking, could pose a risk. More than 130 babies a year die co-sleeping with their parents.
Jenny Ward of the Lullaby Trust said: "Even if parents do not plan to co-sleep, many still fall asleep with babies unintentionally. Babies can and do die in high-risk co-sleeping situations."
The charity, which works to raise awareness of SIDS, found that 40 percent of 8 500 parents surveyed had co-slept with a baby in an unsafe situation. In such circumstances, a baby could stop breathing after being trapped between their parent and the seat of a chair.
Co-sleeping in a bed is not considered dangerous, but experts warn parents to clear duvets or pillows which put a baby at risk of overheating.
The Lullaby Trust advises parents to keep a Moses basket nearby so if they get sleepy they can place the baby in it.
It says co-sleeping should be avoided if a baby was born prematurely before 37 weeks.