The baby would normally be placed on their double bed on its stomach, with its arms up beside its head and its head facing its mother and resting on a tri-pillow.
But one night in August last year, the couple decided to watch movies in the lounge and put together two mattresses. They set the baby stomach-down with arms up by its face and head turned sideways.
Some time in the night, the baby's mother heard the baby grizzle.
Later, at 4am, she found the baby face-down on the pillow, picked it up, found that it was cold and no longer breathing. She quickly dressed the baby in warmer clothes and both parents tried performing CPR on it without success.
A pathologist gave the cause of death as position asphyxia, which may have occurred when the baby slipped down its pillow and its face became covered by soft bedding.
Plunket workers had been scheduled to visit just three days after the death.
Dr Bain has been outspoken on the issue, likening the practice of bedsharing to "Russian roulette" and often commenting that parents were unwittingly killing babies by sleeping with them.
Dr Bain noted there had been enormous media coverage surrounding the high-profile child abuse deaths of Nia Glassie and Chris and Cru Kahui, yet many more babies were being lost to bedsharing.
"It's tragic for a family to lose a baby in these circumstances - it's even worse to know that you could have 100 per cent prevented that."
Twenty babies died each year of SUDI in South Auckland alone, largely in Maori, Pacific Island and low income families. Agencies had responded by distributing hundreds of Pepi Pods, which allowed babies to lie safely next to parents when sleeping in an adult bed, on a couch or away from home.
A study was also under way there to find how best to push safe sleeping messages to parents and reverse bedsharing habits that had been in place for generations.
"I would say it's not so much a cultural thing," said Dr Christine McIntosh, a Papatoetoe GP and SUDI researcher. "It's more somebody taking the time to work out what the needs of those families are, and giving them the information at a level they understand."
Professor Ed Mitchell, a child health researcher at the University of Auckland, said the biggest issue was many of these families were not even receiving the information.
"The message remains that the safest place to sleep is in a cot beside the parental bed for the first six months of life ... it's not rocket science."
Safe Sleeping
• Sleep baby in their own cot or bassinet.
• Make sure the mattress is clean, dry and fits snugly.
• Make sure baby's face is well clear of bedclothes.
• Place cot in same room as parents' bed.
• Put baby down to sleep on their back.
Source: Plunket