A young mother found guilty of severely injuring her toddler wants to be a responsible mother and gain custody of her second baby, a court has heard.

The woman, now 22, and her then-partner, 24, were both found guilty of criminal neglect by District Court judge Jack Costello in April.

The court heard the woman was 17 when she gave birth to her daughter and lacked a maternal bond with her child.

In 2013 the toddler was so badly injured she was possibly days, if not hours, from death when her grandparents took her to hospital in an unconscious state.

Judge Costello found the woman inflicted a number of "high impact forceful blows" to her toddler, causing multiple bone fractures and serious internal injuries.

He found her partner failed in his duty of care to the child and also did not seek medical attention for the toddler.

During sentencing submissions today the woman's lawyer, Nick Healy, said his client had taken steps to rehabilitate and wanted to regain the care of her baby.

"She is someone who was extremely naive, who found herself in a position of being a mother at a very young age and lacked really the necessary insight about the responsibility that goes along with having a young child," Mr Healy said.

"She is working with Families SA at the moment undergoing constant assessments.

"Since your honour's conviction she has given birth to another young child. [He] has been taken out of her care."

Mr Healy said his client accepted she had been "neglectful" and urged the judge to suspend any prison sentence.

Child 'scarred for life', grandparents say

Lawyer for the woman's former partner, Matthew Mead, also asked the court to suspend his client's jail sentence.

"He's not unaffected by what has occurred to [the girl] and perhaps has less insight into his role in what occurred to [her]," Mr Mead said.

Prosecutor Chris Edge said it was very serious offending and it was important to deter others from similar crimes.

"The harm is at the high end of the scale, the child was in severe pain and as your honour knows she was close to death," Mr Edge said.

"What is clear in this case is the striking absence of any real contrition, remorse or insight by either accused."

The woman's parents, who now care of their young granddaughter, told the court through a victim impact statement of the devastation they felt when their "happy, smart" granddaughter was hurt.

"She knows what happened to her and she knows she was hurt and she will live with these scars for the rest of her life," they said in their statement.

"When [she] was injured we were devastated, it was like the world turned upside down, it was very difficult for us to take in, we were in turmoil trying to come to terms with what happened."

Judge Costello said he regarded the crimes as "very serious" and would deliver his sentence on August 12.