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 NHS 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.
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 who responded 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.
Chief executive of the Royal College of Midwives Cathy Warwick 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.”
Jenny Leggott, Director of Nursing and Midwifery at Nottingham University Hospitals, said: “Around 10,000 babies are born every year at our hospitals and very regrettably a small percentage of women do not have their baby at NUH when our units close, most often due to demand on our services and short staffing due to last minute sickness absence. We never turn patients away at the door.
"On the occasions our units are closed, patients who live closer to Derby, Leicester or King’s Mill are given the option of going there. Some women decide they don’t want to travel and opt for a home birth.
"We review every closure to understand if we could have managed it differently."