A fertility specialist who dedicated her life to helping others to have children but suffered a series of miscarriages herself has given birth to a girl after receiving controversial medical treatment.

Kathryn Berrisford, an embryologist at the CARE fertility clinic in Nottingham, lost four babies to miscarriages before seeking out the specialist treatment. "After the third miscarriage I began to think something serious was wrong. After another baby was lost we had to find out why."

After standard tests failed to identify the cause of the miscarriages, George Ndukwe, the fertility centre's clinical director, suggested a treatment known as lymphocyte immune therapy.

Tests showed that Mrs Berrisford, 33, and her partner, Joss, had the same type of a specific antigen protein in their immune systems. It meant that in the early stages of pregnancy Mrs Berrisford's immune system was defective, and was rejecting the foetus each time.

The treatment involved a controversial technique. Some white cells from the blood of Mrs Berrisford's partner were used to immu nise her body, enabling her to adequately protect the growing foetus. "The next time she became pregnant, her body responded naturally," said Dr Ndukwe.

Mrs Berrisford received the treatment in August 2004 and became pregnant shortly afterwards.

The baby, a healthy girl named Mae, was born two weeks ago.

"It was like a miracle because when you have really thought that you can't have a child of your own and to be in despair about it, to actually then get it is amazing," said Mrs Berrisford. "Mae is the best thing that ever happened to me."

However, Dr Ndukwe emphasised that this type of treatment was not accepted by all doctors in the field and it worked effectively only in a small minority of cases.

He Ndukwe added: "Some people say that it doesn't work, but my view is that there are so many different causes for miscarriage, so there is no treatment that will work for everybody.

"We are, of course, relieved and delighted that this special little girl is finally here. It was particularly hard for Kathryn because she was so involved in helping other couples have a child."