Kathleen Joyce, an inmate at Risley prison, Cheshire, had managed to conceal her pregnancy for more than three months after being admitted to the jail in November.
In the early hours of yesterday morning she gave birth to a 3lb 2oz baby girl, who was born two months premature.
The mother and baby were taken yesterday to the Warrington General hospital where the baby is now being monitored in the special care unit. Joyce, who is about 40, was taken back to her cell at around lunch-time.
It is understood that Joyce, who is in the prison on remand in connection with an alleged assault in Blackpool last year, was asked if she was pregnant when she was admitted to the jail. She said that she was not and refused to take a pregnancy test.
Joyce is at present under observation for psychiatric problems in an individual cell on the health care unit where staff believe that she was not aware that she was pregnant until going into labour.
Staff at the prison blamed the oversight on the lack of female doctors and prison officers working at the jail where inmates are dependent on male locums for medical treatment.
Some prisoners refuse help rather than be treated by a male doctor and others have been alarmed by reports that pregnant inmates have been handcuffed to hospital beds during the later stages of their pregnancies.
It is prison service policy to allow pregnant inmates to have their babies in local hospitals.
A prison service spokesman said last night: "At about 3am a baby was born to a prisoner in Risley prison. The mother and baby were transferred immediately to a local hospital and they were both well."
The birth comes only two days after serious criticisms of Risley and other women's prisons by Sir David Ramsbotham, the chief inspector of prisons.
Sir David said women inmates were having to endure "unacceptable" conditions with widespread abuse and overcrowding. He called for a Director of Women's Prisons to be appointed.
Next week an inquest is due to take place into the death of another female inmate in a suspected suicide at Risley last summer.
The coroner is understood to have asked for a copy of the Chief Inspector's report on the jail which followed an inspection carried out close to the time of the death.Reuse content