SINGAPORE - The death of a 15-day-old baby boy could have been caused by "unintentional suffocation" after his mother nodded off while breastfeeding him in September last year.

She woke up about 1½ hours later and found the infant unresponsive with vomit residue on his cheeks.

Baby Nor Eilshan Emran Muhammad Nor Aszroy was pronounced dead in hospital about two hours later at around 5am on Sept 1 last year.

In an inquiry last week into his death, State Coroner Kamala Ponnampalam said there was no basis to suspect foul play in this case and added that his death was likely to have been the result of "unintentional suffocation".

As the medical cause of Nor Eilshan's death is unascertained, she said: "I am constrained to record an open verdict."

The mother's name was not revealed in court documents seen by The Straits Times.

The baby was born at KK Women's and Children's Hospital (KKH) on Aug 17 last year and a routine screening conducted that day revealed no abnormalities.

While still in hospital, the mother declined the nurses' offer to teach her how to breastfeed.

She said she had breastfed her firstborn, a daughter, who was then 17 months old.

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In the ward, the nurses observed her breastfeeding Nor Eilshan and left when they saw that she was progressing well.

Senior nurse manager at KKH, Ms Teo Puay Ling, had said that there are two preferred breastfeeding techniques.

One is the "football hold" position where the baby is tucked under the mother's arm like a football.

The other is the "modified cradle hold", where the baby is held in the crook of the arm opposite the breast he is feeding from.

State Coroner Kamala said: "(Ms Teo) stated that (KKH) does not encourage the 'side lying' method to avoid unintentional suffocation should the mother fall asleep during breastfeeding.

"Mothers may feel sleepy and doze off when the relaxing hormone oxytocin is released during breastfeeding... It is then important to have another person present to put the baby back in the cot if the mother falls asleep."

Both mother and son went to his maternal grandparents' home in Sengkang after they were discharged from KKH on Aug 20 last year.

Twelve days later, at around 1.30am, the mother fed Nor Eilshan with her left breast by using the side lying method.

While doing so, she fell asleep with her left arm stretched out above her head and underneath a pillow.

When her husband woke up at around 3am to use the toilet, the noise woke her up.

She felt "something wet" as she moved her left hand to lift the baby and asked her husband to turn on the lights.

She then found her son unresponsive, with vomit and bloodstains on his swaddling cloth.

He was taken in an ambulance to Sengkang General Hospital, where he was pronounced dead at around 5am.

Associate consultant forensic pathologist Belinda Lee had stated that his cause of death was "unascertained".

The post-mortem external examination also showed no internal or external injuries.

The state coroner said in her findings that according to Dr Lee, it was plausible that the baby had suffocated while his mother was asleep.

Dr Lee had also said suffocation can occur when an infant's nose and mouth becomes obstructed by pillows, bedding material or other people when they sleep together on the same bed.

This obstruction could then lead to a lack of oxygen supply, and death.