The maternity unit at York Hospital was closed to women in labour 14 times in August as the service experienced “unprecedented times”.

Chief nurse Heather McNair said staffing pressures at York and Scarborough Teaching Hospitals NHS Foundation Trust were “immense”.

According to a report to the trust’s board: “The teams continue to work under significant pressure and above and beyond to ensure a safe service and should be recognised for this.

“Maternity service[s] are [experiencing] unprecedented times and the acuity and complexity of the women we care for is increasing”

The maternity unit at York was either closed altogether – or in a position where new women had to be diverted away – on 14 occasions last month, a “significant increase on previous months”, according to the report.

Inadequate midwifery staffing and insufficient bed space on the postnatal ward were the common themes for unit closures and diverts.

Women were primarily diverted to the unit at Scarborough, but also to other units, Ms McNair said.

At the end of last year, a board report showed that a whistleblower had raised concerns that maternity services at the trust were “so unsafe as to be putting women and babies lives in danger every day”.

The concerned staff member said some community midwives were working shifts of almost 24 hours a day.

The whistleblowing concern was not upheld by the trust, however, which said staffing figures appeared “good overall with some areas for improvement.”

The latest figures showed a midwife vacancy rate of nearly 14 per cent at York. There are “significant gaps in the roster across the service” and more agency staff are having to be drafted in.

Two wards at York have been merged to increase the number of midwives and health care assistants available on the wards.

In August, there were two serious incidents in maternity services that were also reported to the healthcare safety investigation branch (HSIB) – one maternal death at Scarborough and one intrauterine death of a baby at York.

The latest board report also noted that there had been six intrapartum stillbirths in the last twelve months, compared to just one in the year before.

This is part of a wider pattern and Ms McNair said work was going on nationally to try to find out why this was happening.

A Care Quality COmmission inspection of maternity services at York is expected before Christmas.