The new unit is intended to help secure the hospital's future

Mothers with problems such as severe postnatal depression will be able to keep their babies with them.

The new unit, opening in August, is a further move by NHS Lothian to help secure the future for the hospital.

It follows the transfer of an ear, nose and throat service to St John's from the Western General in Edinburgh.

NHS Lothian chairman Brian Cavanagh said: "We have always said that we are committed to developing the facilities at St John's and ensuring that it has a vibrant and exciting future.

"St John's is an important part of our vision for how we will continue to deliver excellent services for the people of Lothian.

"This new unit will enable mothers to have their babies with them at a time of personal difficulty and this will hopefully be a comfort for them."

Linda Irvine, programme manager for mental health and well-being for NHS Lothian, said: "At the moment, it is difficult for new mums who need inpatient treatment for mental health problems to have their babies with them in hospital.

Focus group

"This new unit will mean that mums and babies can stay together, which is in everyone's interests.

"We plan that the unit will be as home-like as possible and a focus group of mothers has played an important role in advising us on what they would like."

The unit will be open to women from a large part of Scotland.

A specialist perinatal team will work with all community mental health teams across Lothian to help mothers receiving treatment at home.