Tori Shipman, now 21, fell asleep at the wheel as she drove west along the New England Highway towards the Hunter Valley region in August 2015.

Her car collided into a concrete pylon with her daughter, Jannali, who she had allowed to sit in the front passenger seat instead of in her baby carrier, was thrown through the passenger side window and died.

Delivering his sentence in the Downing Centre District Court on Thursday, Acting Judge Norman Delaney said that Shipman had suffered an "indescribable tragedy" and questioned what further punishment could be delivered to somebody in her situation.

Backdated to include the nearly 13 months she has already spent in custody, Shipman will be eligible for parole in March next year. 

Shipman pleaded guilty to dangerous driving occasioning death and dangerous driving occasioning grievous bodily harm, admitting that she was sleep deprived and had smoked cannabis and used ice before getting behind the wheel.

At the time of the crash, she was serving sentences for other offences and her learner's permit had been disqualified for three months for driving unaccompanied.

Acting Judge Delaney outlined Shipman's difficult and dysfunctional childhood in northern NSW, including her exposure to domestic violence, sexual abuse, criminal offending and drug use. 

From a young age she had learnt to fend for herself, and she had started using cannabis from the age 14 and later ice because it made her feel like "like nothing in the world mattered". 

Mr Delaney said the effect the death of her child would have had on Shipman was "inconceivable", noting how she was seen screaming hysterically at the scene of the crash.

Shipman also wrote a letter to the judge apologising for what had happened.

"The choices I have made have not only affected myself but people I love more than anything in the world," she wrote in the letter. "My life has changed drastically in a way I can never explain."