A month-old baby who slept with her parents was found unresponsive hours later with vomit residue on her face and foam in her mouth.

The baby was rushed to Khoo Teck Puat General Hospital, but was declared dead soon after.

Yesterday, in the inquest into the child's death, State Coroner Marvin Bay could not pinpoint exactly why the New Year Day tragedy happened, but he urged parents to be mindful of the possible hazards when sharing their bed with their young ones.

To cut the risk of accidental smothering, he said infants should be placed in their own cots.

"While the exact circumstances of the baby's sad demise cannot be clinically ascertained, there are real potential hazards inherent in the practice of very young infants sharing their beds with one or both parents, or other caregivers, which parents should be mindful of," he said.

Investigations showed that at 8am on Jan 1, the baby's mother, a 31-year-old housewife, took the crying child from her cot to her bed to breastfeed her.

The baby did not burp afterwards despite the mother's efforts. Burping is one way parents can help babies get rid of gas that may be trapped in the gastrointestinal system.

At noon, the 33-year-old self-employed father woke up to prepare for Friday prayers. He did not notice anything amiss.

When he was on his way out, he woke his wife up to say he was leaving. His wife then saw that the bed area where the baby slept was wet.

On checking, her husband realised that there was vomit residue on the baby's face, and foam in and around her mouth. She was not breathing, and despite attempts to rouse her, she remained unresponsive.

He shouted for his wife to call emergency services as he tried to resuscitate her.

A forensic pathologist could not ascertain the cause of death.

In her report, pathologist Belinda Lee stated that since the baby was co-sleeping with her parents, it is not possible to rule out she had been accidentally suffocated by a pillow, bed sheet or a body part of a parent.

But it was also not possible to rule out that her death was related to sudden death infant syndrome (Sids). This affects children below a year in age, and usually occurs during sleep. The exact cause of Sids is unknown.

KK Women's and Children's Hospital records showed that the baby was premature and delivered after an emergency caesarean section at 36 weeks. But she was born healthy.

The parents, who have three other children, did not attend the inquest.

Speaking to The Straits Times, Dr Janice Wong, a paediatrician at Thomson Paediatric Centre, said parents are always advised not to sleep with their baby, who should be placed in a cot. This is to avoid the risk of rolling onto the baby and possibly causing the infant to suffocate.

Even when babies are put in cots, safety measures have to be taken.

Dr Wong said the cot has to have no pillows or stuffed toys in it, and blankets have to be tucked in tightly so that they will not cover the baby's face.

She acknowledges that parents may choose to sleep together with their baby to make breastfeeding more convenient. Parents also worry about leaving babies on their own at night.

But Dr Wong stressed: "The cot is where the baby should be sleeping. If parents want to monitor their baby, get a baby monitor."

She highlighted a recent case she attended to in which a two-week- old baby fell off the bed and suffered a head fracture.

"There is absolutely no advantage for the baby co-sleeping with parents, the advantage is for the parent - they have ease of care."

Convenience should never be a factor for parents to co-sleep with their baby, she added.

•Additional reporting by Trina Anne Khoo