An investigation has been launched after a woman that had been in a vegetative state for 14 years gave birth inside the facility where she is a patient.

The woman, who has not been named, has been in a persistent vegetative state since a near drowning. She gave birth to a baby boy on December 29, KPHO reports.

She had been at the Hacienda HealthCare facility for over a decade the incident occurred.

Staff noticed she was moaning and realised this she was in labour. Nobody had realised that she was pregnant.

"There was a nurse that was there, and from what I've heard she's the one that delivered the baby," a source from inside the facility told KPHO.

The Phoenix Police Department has launched an investigation into how the woman became pregnant. Several other agencies have also become involved, including the Department of Economic Security.

The Arizona Department of Health Services has also initiated an onsite complaint investigation at the facility.

"During this time, the agency has required heightened safety measures be implemented at the facility including increased staff presence during patient interactions, increased monitoring of the patient care areas, and increased security measures with respect to visitors at the facility," it said in a statement.

Arizona State Governor Doug Ducey called reports of the situation "deeply troubling".

"We are re-evaluating the state's contract and regulatory authority as it relates to this facility and have been working closely with state agencies to ensure all necessary safety measures are in place," a spokesperson for Mr Ducey said.

Male staff members at the facility are now required to have a female chaperone when entering the room of any female patients.

The baby is reported to be in good health.

Newshub.