A pregnant Adelaide drug trafficker has been granted bail after arguing her children would suffer separation hardship and she would not be able to breastfeed her new baby if she continued to be jailed.

Sorayah Louise Constant, 31, who is pregnant with her second child, was originally jailed for at least 18 months for drug offences, her crimes breaching a previous good behaviour bond for drug trafficking.

Her lawyer Heather Stokes argued throughout the sentencing process and on appeal that the lack of a mothers and babies unit at the Adelaide Women's Prison meant Constant's now 23-month-old daughter and her unborn child would suffer separation anxiety and hardship.

Ms Stokes also said her client would be prevented from breastfeeding her new baby because the baby would be removed from her after birth due to the lack of facilities in prison to accommodate infants and children.

The Court of Criminal Appeal allowed Constant's appeal and reduced the non-parole period on her revoked suspended sentence so she would be eligible to seek parole on that offence on August 17.

Justice David Lovell has now granted Constant bail, meaning she is expected to be released from prison on Wednesday when that non-parole period expires.

Constant, who watched proceedings through a video link from prison, cried.

Danielle Constant, Belinda Lee and Tracey Constant outside court. ( ABC News: Candice Prosser )

The Court of Criminal Appeal will reconvene in March to consider its re-sentence and any evidence of Constant's rehabilitation.

Outside court Constant's family members expressed relief and happiness at the decision to release Constant.

"I think we all got a bit emotional, yeah, very happy," sister Danielle Constant said.

"She's due to give birth in October so we're very grateful she'll be out before the birth of her child."

She said her sister was a good mother.

"She's a very good mum, very good person, best mum, best sister, she's just beautiful."

Constant's mother Tracey Constant said her daughter had rehabilitated.

"She's a fantastic mum. She really changed her life, you know, having children really changed her," she said.

"She's changed her life around, this happened so long ago so it's just good that she can be out."

Incarcerating mother without baby 'harsh': court

In its judgment, which was published on Monday, the Court of Criminal Appeal said although it did not lose sight of the seriousness of Constant's offending, it considered incarceration in all the circumstances to be "harsh" and "counterintuitive".

What happens to mothers in prison? Correctional services in New South Wales, Victoria, Western Australia, Queensland and Tasmania all have live-in facilities for children of mothers in custody

Correctional services in New South Wales, Victoria, Western Australia, Queensland and Tasmania all have live-in facilities for children of mothers in custody A pregnant woman in custody at the Adelaide Women's Prison would be taken to hospital to give birth, stay in hospital for a period determined by the hospital to allow her some recovery, then be separated from her baby

A pregnant woman in custody at the Adelaide Women's Prison would be taken to hospital to give birth, stay in hospital for a period determined by the hospital to allow her some recovery, then be separated from her baby The baby would be taken into the care of family or social services, and the mother would be returned to prison

The baby would be taken into the care of family or social services, and the mother would be returned to prison A mother in custody in SA could be visited twice a week by her children, on Saturday and Sunday for up to three hours, but only 12 such visits for all prisoners in the prison can be accommodated on each day in total. To date, the 12 visits have been enough to cope with demand.

"It is harsh at any time to separate a newborn child and its mother, but here where motherhood has proven to be the avenue through which rehabilitation has been achieved and in all likelihood will be maintained, it is not only all the more harsh but counterintuitive," the court said.

"We have concerns that incarceration of the applicant after she gives birth may be a price too high, considering both the applicant's dependents and the fact that imprisonment is significantly more burdensome for a woman in South Australia who gives birth whilst in custody."

The court said although it was important to have consistency in sentencing federal offenders, incarceration of a mother in South Australia was "more punitive" than other states because of the lack of mothers and babies facilities.

The court said removing a newborn child from Constant soon after birth would be "undeniably painful".

"We have no doubt that such an act would be traumatising and has the potential to have lasting psychological consequences," the court said.

"Motherhood, it appears, is one area in life where the applicant is intent upon, and so far proven capable of, making a difference."

The court said the "importance of the development of our children to the future prosperity of the community cannot be understated" and attachment bonds were crucial to a child's development.

A Corrections spokesman said the demand for a mothers and babies unit was low, and did "not warrant the department investing and focusing" on it.

"Over the last five years, less than six women and children in South Australia would have been suitable for accommodation within a mothers and babies unit," he said.

He said the department already had a range of strategies to assist mothers and children.