A nurse has been arrested after a woman who has been in a vegetative state in the US for years gave birth at a long-term health care facility.

Phoenix police said a male licensed practical nurse has been detained on one count of sexual assault and one count of vulnerable adult abuse.

They named him as 36-year-old Nathan Sutherland.

He worked at the Hacienda HealthCare facility on the outskirts of Phoenix, Arizona, where the woman lived, and had been providing care to her, Phoenix Police Chief Jeri Williams said.

The 29-year-old victim has been incapacitated since the age of three after an incident in which she nearly drowned.


Image: The woman is a patient in a clinic run by Hacienda HealthCare in Phoenix. Pic: Google Street View

Employees at the facility said they had no idea she was pregnant until she started going into labour and gave birth to a healthy baby girl on 29 December.

Court records say her last known physical was in April.

Phoenix Mayor Thelda Williams said police had been working "around the clock to make an arrest in this horrible crime".

Phoenix police have made an arrest in the sexual assault of a vulnerable adult at a health care facility. I’m proud of the women & men of @phoenixpolice who worked around the clock to make an arrest in this horrible crime. My thoughts & prayers are with the victim and her family. pic.twitter.com/epLJBGXKnJ — Thelda Williams (@TheldaWilliams1) January 23, 2019

After panicked staff called police when she gave birth, investigators demanded DNA tests from all male employees.

On Wednesday detectives said the DNA samples led them to charge the nurse.

The woman is a member of the San Carlos Apache tribe, where chairman Terry Rambler earlier said the community had been left "deeply shocked and horrified" by her treatment.

After the shocking birth was publicly revealed the private clinic's boss, Bill Timmons, resigned.

Audio from the 911 call by nurses after the birth revealed them telling the operator: "One of the patients just had a baby and we had no idea she was pregnant.

"The baby's turning blue and we need someone now! This is a complete surprise. We were not expecting this."