Parents of a very ill and weak diabetic daughter could have saved her life by making a single phone call to a doctor, an Adelaide court has been told.

The 14-year-old triplet, who only weighed 28 kilos when she died, was drowsy, weak, vomiting, had a seizure and high blood glucose levels in the week before her death, prosecutor Carmen Matteo said.

"Her condition was treatable, therefore her death was preventable," she said in the South Australian Supreme Court on Friday.

Richard David Edward, 50, and Debra Marlene Edward, 53, who have separated since the death, have pleaded guilty to causing Dawn Edward's death by criminal neglect.

Dawn, who suffered from type 1 diabetes and was insulin dependent, died on August 9, 2009, at the Hackham West family home she shared with her parents and four siblings.

She died of hyperglycaemia and dehydration.

Since her diagnosis in May 2007, Dawn was subject to a strick regime for the management and monitoring of her condition, including checking her blood glucose levels and her diet.

Ms Matteo said the parents failed to seek or obtain medical assistance in the week before Dawn's death when she was obviously sick.

"The step that could have reasonably have been expected to be taken here amounted to the making of a telephone call," she said.

The court was told the mother was intellectually-disabled, while both parents were of low intellect.

Both had been educated about their daughter's condition and warned about the danger signs for seeking medical help.

Dawn had been hospitalised previously when she was "skin and bones", extremely dehydrated and vomiting, Ms Matteo said.

Richard Edward's barrister, Justin Wicken, said his client had believed Dawn had been suffering from gastroenteritis.

"It was complete failure on his part to appreciate the seriousness of the situation," he said.

Edward was extremely remorseful, understanding that he had caused his wife and Dawn's siblings "a great loss".

"If he could go back, he would have no hesitation in making that phone call early in the week," Mr Wicken said.

They will be sentenced on a later date.

 

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