Rotorua police constable Heidi Jessen told the inquest Ivan's mother, Cherie Karaitiana, slept with him in a double bed, where they would normally top and tail, while his siblings would sleep in bunk beds.
A week before his death, Ivan had a chesty cough and a runny nose sometimes in mornings.
At 10pm on September 14, Ivan's mother fed him a bottle of formula and put him to bed, covered by his own baby blanket and those of his mother.
Later, Ivan did not wake during the night for his feed as normal.
Ms Karaitiana later told police that whatever happened to Ivan, occurred between 5am and 6am.
His father would check him "without fail" when he left for work at 5am.
"I woke up at 10 to six. Ivan was cold, I went to wipe his nose," Ms Karaitiana told police.
Noticing his head was cold, she put a blanket on him and discovered his arms were stiff.
"She shook him and he didn't wake up," Ms Jessen said.
'She picked Ivan up and ran to the neighbours, where emergency services were called."
A limited-post mortem examination found no unusual circumstances or substances.
It was the doctor's opinion that the cause of death was due to unsafe sleeping practices.
Dr Bain reserved his findings, but remarked that the death was "one of a number that keep occurring".
He referred to comments he made last month at an inquest into the death of a Tauranga two-year-old, highlighting the disproportion of media coverage of high-profile child abuse deaths to those lost to unsafe sleeping.
"It's almost like an epidemic," he said.
"The message has just got to get out there."
Dr Bain also noted how coroners in Australia, England and Ireland had recently condemned bedsharing, and acknowledged New Zealand efforts to address the problem, among them protective pepi-pods for babies to sleep in alongside their parents.
The inquest comes after a newly released study by the University of Auckland found bedsharing multiplied a child's risk of SUDI five times, even if the parent is a non-smoker and has not consumed drugs or alcohol.
While there was a general consensus that sleeping with a baby increased the risk of death if the parents smoked or if the mother had been drinking alcohol or taken drugs, previously there had been conflicting opinions about whether bed sharing represented a risk when these factors were not present.