"I was totally exhausted." Romy Zunde was fatigued when she left baby Noah in the car.

Romy Zunde was so sleep-deprived she thought she had dropped her toddler at childcare, but she had not, and he died sweltering in his family car – a victim of forgotten baby syndrome.

A Victorian inquest into the death of 22-month-old Noah this week was told that kind of memory failure could happen to anyone.

The week Ms Zunde’s son died in 2015, the family had gastro, their pet pigs were attacked by a dog that had to be euthanised and Noah was teething and irritable.

Mrs Zunde’s parents were also coming to stay, she had to clean the house and the childcare routine had changed.

“I was totally exhausted,” she later told police.

“I was so confused. I had a clear memory of dropping him off. I think my memory was thinking of the day before.”

Noah was found in the back seat of his family's Toyota Hilux outside his childcare centre in Kyneton on a hot day in February 2015.

He had been there for seven hours when Ms Zunde discovered Noah was not where she believed him to be.

Noah's death is one of two being investigated by Victorian coroner Sara Hinchey, in which a young child died after being unintentionally left in a car.

This week, counsel assisting the coroner Jodie Burns said the death met the definition of a homicide.

But the coroner could not be convinced an indictable offence had been committed due to the circumstances surrounding the death.

The inquest was told that on the day before Noah's death, Mrs Zunde felt she "needed help" for fatigue but could not ask for it.

Ambulance Victoria attended 1907 cases of children left in cars in 2016, 28 of which required hospital care.

In the past 10 years, coronial records show at least five children died after being left in motor vehicles.

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Monash University associate professor in psychology Matthew Mundy said short-term memory was impaired by distraction, stress and sleep deprivation.

"We're talking about an extended period of sleep deprivation," he said of Mrs Zunde.

"There are a number of stressors, some of which had been building up over several days.

"I believe this kind of memory failure could happen to anyone."

He said whether it was forgetting to post a letter or forgetting a child in the car, the brain did not discriminate when distractions were at play.

Ms Burns urged the coroner to recommend authorities consider safety technology be included in vehicles to remind parents their children were on board.

The case was adjourned to a date to be fixed.