Maternity units at a hospital trust in England had to close 97 times in the past year, figures show.
The closures across Nottingham University Hospitals Trust, which covers Nottingham City Hospital and the Queen’s Medical Centre, were revealed after a Freedom of Information request by the BBC.
Just over half of the trusts who responded to the request for information had to close for a time in 2013.
“If units are regularly and persistently having to close their doors to women it suggests there is a serious underlying problem”
The main reasons for temporary closures were lack of staff and beds, the BBC said, adding that many of the closures lasted a few hours but some were closed for more than 48 hours.
Of the trusts in Wales that responded to the information request, four had closed for times ranging from short periods to over 24 hours.
Trusts in Scotland and Northern Ireland did not report any closures, the BBC said.
Cathy Warwick, chief executive of the Royal College of Midwives, said regular or persistent closures suggest “a serious underlying problem”.
“Birth is unpredictable and sometimes units get a rush of births that is unavoidable and cannot be planned for,” she told the BBC.
“However, if units are regularly and persistently having to close their doors to women it suggests there is a serious underlying problem.”
Commenting on the figures, health minister Dr Dan Poulter said mothers-to-be were being offered more choice in maternity care.
He said: “The number of midwifery-led units has almost doubled since 2010 and more women live near a range of services to choose from.
“There will always be very limited occasions when a maternity unit cannot safely accept more women into their care and may need to close temporarily,” he said. “Any decisions to redirect women are made by clinicians as part of a carefully managed process.”
He added: “We have invested £35m to improve maternity units across the country and now have over 1,700 more midwives – with 6,000 more in training since 2010.”