If Melissa Drexler had been British, her fate could have been very different.

Instead of facing 15 years in prison for aggravated manslaughter after discarding her new born child in a school toilet, Ms Drexler, dubbed "Prom Mom" by the US media, would be considered in need of medical help.

Murder or mental illness?

The difference between the US and UK treatment of infanticide was highlighted in 1994, when a British woman, Caroline Beale, was imprisoned in the United States after being arrested trying to take her dead baby through customs at JFK airport.

Caroline Beale: Treated like a common criminal

Ms Beale's family asked Professor Channi Kumar, a psychiatrist at the Maudsley Hospital in London, to visit her in Rikers Island prison in New York for a psychiatric assessment, evidence later presented in court.

He said the conditions under which she was detained were so horrific that he had nightmares.

Professor Kumar, who continues to treat Ms Beale in the UK, says it is widely recognised that women are at risk of mental illness after childbirth.

Most women at the time of childbirth go through a period of adjustment because of the huge changes that are taking place in their bodies.

As their hormone levels readjust, women usually experience new emotions that they channel into love and affection for the baby, says Professor Kumar.

"But sometimes this goes wrong, in which case they need medical help, not prison."

The law in the UK recognises the potential for mental imbalances up to 12 months after childbirth - if found guilty of the crime of infanticide, women are generally managed on probation orders, and given medical treatment.

But, according to the American lawyer who defended Ms Beale, Michael Dowd, the situation in the US is radically different.

"Without exception the authorities view infanticide in the same way as they would a contract killing - cold-blooded murder and nothing more."

He said these attitudes were key to the kind of sentence given to Ms Drexler.

"Here, it [her sentence] is being seen as her getting a good deal - 15 years," he said.

Concealed pregnancies

Professor Kumar says Ms Drexler's behaviour is a classic symptom of vulnerable young women with unwanted pregnancies.

She kept her pregnancy secret from everyone, including her boyfriend.

"Sometimes psychological denial is the only way of coping with it," Professor Kumar says.

"Some women may even have difficulty in recognising the baby as a person."

This phenomenon is especially common if the woman has a troubled family life, or if she is of low intelligence.

Ms Drexler's lawyer, Steven Secare, said his client was an example of a woman with a developmental and learning disability.

Caroline Beale also concealed her pregnancy - even from the friends who she was on holiday with when she gave birth.