Rosie Cox was born 15 weeks premature and weighed 1lb 14oz, or 856g.

Her tiny size is emphasised when you consider an average adult loses her entire body weight in sweat after an hour's run.

She is now four weeks old and weighs an ounce less than at birth.

Rosie's home for the first month of her life has been an incubator in the Special Care Baby Unit, at the Great Western Hospital. Her parents Helen Cox, 35, and Shawn Baker, 36, say she is doing well following heart surgery last week.

Shawn, a fabricator, from Church Street in Wootton Bassett, said: "Rosie's valve on her heart wasn't closing properly so she had to have an operation to attach a clip onto it.

"She's still quite sedated but she is doing really well. When she was first born everyone thought she wouldn't survive. I was also very worried about Helen because she was losing quite a bit of blood."

Shawn, who is also dad to Leoni, 17, and Jade, 15, from a previous relationship, and nine-month-old Cerys with Helen, said: "Jade has had a cold in the last few weeks and hasn't been able to see Rosie yet. But they are both delighted."

Helen said the birth was as much a shock to her as to everyone else.

"I had no idea I was about to give birth," she said. "I drove up to the hospital in the night thinking I was fine really, and half expecting to be told to go home. I thought the pains I felt in my stomach were normal for someone six months pregnant.

"But instead doctors discovered a clot had started to grow behind the placenta. It was a very scary time.

"I didn't get to hold Rosie for three days. It was incredible to have her in my arms, but very strange because she was so light."

Helen and Shawn are hoping to have Rosie home before her original due date February 23.