Poole Hospital’s maternity unit had to be closed for 27 hours last month because it was unable to cope with any more patients.

During the crisis on August 15 and 16, one woman went to Salisbury Hospital as an ante-natal patient and three other women had their babies delivered at home by community midwives.

A report to Poole Hospital Trust’s board said a number of factors linked to a “high level of activity and complexity” were involved, leading to all antenatal and postnatal beds being fully used. “The staff managed this challenging period well,” it added. A full investigation into the circumstances has been carried out by chief operating officer Mary Sherry.

The unit has 41 beds, including antenatal, postnatal and delivery suites.

A spokeswoman for the hospital said: “St Mary’s Maternity Hospital temporarily closed to admissions for 27 hours in August due to exceptional circumstances resulting from an unusually high number of mothers requiring post-natal care and a sudden increase in admissions.

“No women in labour were required to travel elsewhere as a result of the temporary closure. The maternity hospital has only closed once before – in November 2011 for five hours.”

In 2008, the trust announced its intention to build a new £30 million maternity hospital, but plans were shelved because of financial constraints.

The spokeswoman said Poole Hospital had made a substantial investment in maternity services over the last year.

“New state-of-the-art theatres have been opened and staffing has been increased, with additional midwives, doctors and theatre practitioners now in post. The trust board is currently considering proposals to further improve the quality of the patient environment and increase capacity.”

Edit: this story was updated on October 1 to clarify a reference to one woman going to Salisbury Hospital to give birth. This was a misunderstanding. The patient went to Salisbury Hospital as an ante-natal patient and did not give birth there.