What is infanticide? The rare defence being used by Sofina Nikat's lawyers.

CONTENT WARNING: This post contains details of violence against children, which some readers may find distressing.

In April 2016, Sofina Nikat strapped her 14-month-old daughter into her pram and wheeled her to a nearby park in the Melbourne suburb of Heidelberg West.

When she returned a short time later, the pram was empty.

At first police and the local community were on the hunt for a man the 23-year-old described as 180cm tall, of African appearance, barefoot and reeking of alcohol. This man, Nikat claimed, had knocked her to the ground, snatched Sanaya and fled.

But then came Nikat's confession to police. She said she'd placed her hand over her little girl's mouth and nose, smothering her until she went limp, then tossed her into Darebin Creek. It was there, 17 hours later, that locals found Sanaya's body, partially submerged in the water.

Despite Nikat's admission, the Melbourne mother last week pleaded not guilty to murder. There is another charge, her lawyer argues, that she ought to face instead: infanticide.

What is infanticide?

While a murder conviction could see Nikat imprisoned for 25 years, infanticide carries a five-year maximum sentence in Victoria.

The charge applies to women who kill their children (under the age of two) while affected by a mental disorder related to giving birth to them.

It requires psychiatric or psychological assessment as evidence, which Nikat's lawyers have obtained.

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Melbourne Magistrates Court was last Wednesday presented with the assessment of two psychiatrists who attested that Nikat ought to face the charge. One, Yvonne Skinner, described the mother's balance of mind as "disturbed" at the time of the killing, The Daily Telegraph reported.

According to a police summary released by the court, Nikat was struggling to cope with caring for Sanaya, and had told her cousin she wanted to kill herself and her daughter. The summary also stated that a Fijian imam had told her the toddler was possessed by an "evil spirit" - a claim she believed.

Is it common?

Unsurprisingly, infanticide convictions are rare. Very rare in fact.

It's understood that only four Victorian women have ever been convicted of the charge, including one who drowned her five-week-old baby in 2003, one who assaulted her eight-week-old daughter in 2012 and another who smothered her newborn in 2014.

Those three women each avoided jail time. The fourth may not.

That woman is Akon Guode, the Sudanese refugee who deliberately drove her car into a Wyndham Vale lake in 2015, resulting in the deaths of three of her seven children.

The 37-year-old is currently in custody, after pleading guilty to two counts of murder, one charge of infanticide and one of attempted murder in January this year. An almost-certain prison sentence will make her the only person ever jailed in Victoria after pleading guilty to infanticide.

Guode's lawyer, Marcus Dempsey, told the Supreme Court that while her offending was unfathomable, she had been suffering severe, untreated psychological trauma as a result of the "unspeakable horrors" she'd witnessed during the Sudanese civil war 20 years earlier.

He urged the judge not to impose a life sentence, arguing that her actions had the characteristics of infanticide.

"It's hard to imagine such a perfect storm of woe and misery would ever arise in this woman's life again," he told the court, according to ABC.

Guode is due to be sentenced at a later date.

Nikat's case is ongoing.

What about other states?

In New South Wales, infanticide carries a penalty similar to manslaughter (which is up to 25 years) and applies to the death of a child under 12 months old; in Tasmania and Western Australia it can not be used as a defence for murder as it is considered an alternative offence.

It is not provided for in the remaining states' criminal codes.

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