The Care Quality Commission (CQC) said it was considering a criminal prosecution following the death of a 13-year-old girl at Kettering General Hospital.
Chloe Longster, from Market Harborough in Leicestershire, died from pneumonia and sepsis in November 2022, one day after being admitted to the Skylark Children's Ward.
A coroner ruled her death was contributed to by neglect and the hospital admitted it had failed to deliver the care Chloe deserved.
Her mother, Louise Longster, said in response to the health regulator's statement: "We all have a duty to protect children from harm and this ongoing failure to ensure basic safety has been repeated too often. It needs to stop."
A CQC spokesperson said: "We are currently in the process of making enquiries to establish whether there is reasonable suspicion that a criminal offence has been committed."
They added its inquiries were ongoing and it would "report further" as soon as it was able to.
Chloe, who had no serious underlying health conditions, was admitted to the children's ward with severe chest pain and flu-like symptoms.
During the inquest into her death, evidence was heard that checks that might have alerted doctors to sepsis were not carried out, and painkillers and antibiotic treatment were delayed.
Mrs Longster told the hearing that her daughter was in such pain she had asked whether "she was going to die".
Delivering her conclusion at Northampton Coroner's Court on 11 October, assistant coroner Sophie Lomas said Chloe might have survived if she had received appropriate treatment earlier.
The CQC can use its powers to prosecute organisations or individuals under the Health and Social Care Act 2008 and the Care Quality Commission (Registration) Regulations 2009, without needing the police to do so.
The law states it needs to bring the prosecution within three years of the date of the alleged offence.
The CQC said: "The inquest findings and any subsequent report received from the coroner will be fully considered as part of our follow up and used to inform any decision we make."
It said the health and well-being of people using services was its priority, adding: "If we're not satisfied people are receiving safe care, we will not hesitate to take action in line with our regulatory powers."
Chloe's parents Louise and Dave Longster referred to previous failings at the unit, saying: "Each time the hospital says that lessons have been learnt and action plans implemented.
"Clearly they are wholly insufficient, as it is a continuing theme. There needs to be actual accountability."
The BBC has also seen a letter written to the CQC by the Corby and East Northamptonshire MP, Lee Barron.
In it, he outlined his concerns regarding Kettering General.
The letter said during Chloe's inquest, the assistant coroner Sophie Lomas "found some of the evidence given by medical staff, 'wholly unconvincing'".
"She was considering contacting regulatory bodies, but I understand this is not going to happen after assurances were given by hospital management that steps had already been taken," said Mr Barron in the letter.
"Frustratingly at Chloe's inquest, there was a repeat of similar shortcomings at Jorgie's [Jorgie Stanton-Watts] inquest more than eight years ago.
"Many of my constituents are now asking how many more children will die before steps are taken to improve services and families can have confidence in the care they receive."
Mr Barron asked the CQC what steps it would be taking to act on the findings.
The coroner's office has been contacted for comment.
Julie Hogg, the group chief nurse for the University Hospitals of Northamptonshire, said: "We continue to offer our deepest condolences to Chloe's family for their loss and for failing to deliver the care she deserved.
"We have accepted the findings of the coroner at Chloe's inquest and, as an organisation committed to learning from our mistakes, are supporting the CQC's ongoing enquiries appropriately."
Thirty two providers and individuals were prosecuted by the CQC between May 2023 and May 2024.
The last general NHS hospital to face prosecution was University Hospitals of Derby and Burton NHS Foundation Trust in March 2023, for failures within its maternity services.
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Kettering
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