A prisoner found dead in her cell days after she gave birth was fighting to retain custody of her baby, an inquest has heard.

Michelle Barnes had warned a social worker two months before she gave birth, “if you take the baby, I will go too”, a coroner heard.

The 33-year-old, from Carlisle, was serving a two-year sentence for drugs offences at Low Newton Prison, Durham, when she was found dead in her cell in December.

She was taking methadone in prison in a bid to beat her drug addiction, had mental health issues and a history of self-harm, the jury hearing the inquest at Crook Civic Centre was told.

Ms Barnes was jailed in June last year and found out she was pregnant while in prison.

The jail has no mother-and-baby unit but she hoped to be transferred to one of the five prisons in the country that has one, her solicitor Victoria Rowson told the court.

The lawyer had a series of consultations with her before the birth and was advising her on how to challenge the care proceedings brought by Cumbria County Council which were to be decided after the baby was born.

Ms Rowson said: “Her intention was to be a good mother to her child.”

An interim care order was made after the baby was born in hospital and Ms Barnes returned to prison but there was no final adjudication in the proceedings by the time she was found in her cell.

Ms Rowson said her client had hoped to be transferred to a mother-and-baby unit and to stay there until she was released in the summer of 2016. She could have been released sooner than that with an electronic tag.

The solicitor said Ms Barnes “was not in a weak position”, thanks to the work she had done in prison to address her own problems so it came as a shock to hear that Ms Barnes had died.

The baby’s social worker thought the infant should be placed in care, Durham coroner Andrew Tweddle was told.

Sara Driscoll said: “We believed there was a very good reason, a historical reason, why we had to look at that being the only option. It was not a decision taken lightly.

"We believed there was no safe decision for the child, other than removing the child from birth. There was one occasion during one of my visits that she said ’If you take the baby, I will go too’. I passed that on to her mental health worker.”

Related: Carlisle woman found dead in prison cell days after giving birth

The social worker agreed with the coroner’s suggestion that this was something said “in the heat of the moment”.

The most senior governor at the prison, Alan Richer, said the jail had room for 350 prisoners and there were 274 inmates at the time of her death.

Ms Barnes was living in a Psychologically Informed Planned Environment (PIPE) unit – a discrete area of the prison for 40 inmates aimed at helping them overcome issues with the help of specially trained staff.

The inquest continues.