AS Catherine Gwynne cradles her six-week-old baby girl she gazes at her in awe.

And it is little wonder because this tiny baby, named McKenzie Grace, defied all the odds to be born.

Catherine, of Ebbw Vale, had weekly blood tranfusions in Bristol and Cardiff during the pregnancy because her body was attacking her own child.

Each of the treatments could have led to her losing the baby, and there were several terrifying moments during the transfusions.

McKenzie was then delivered ten weeks early in December, after Catherine and her partner Ian had to make the heart-breakingly difficult decision between the risks of prematurity and of leaving her in the womb.

Now, in a house that so obviously contains a newborn - stacks of pink cards, teddies and other baby paraphernalia - McKenzie is quietly oblivious to the drama that surrounded her birth.

But the problems for 30-year-old Catherine began long before McKenzie's incredible story starts.

Although she had her daughter Zoe, now 12, from a previous relationship without any difficulties, when she and 27-year-old Ian began trying for a baby seven years ago they had no success. "We were told Ian had a low sperm count and that I wasn't producing enough eggs," Catherine recalls.

"We thought about IVF but decided against it. We had Zoe and that was enough."

But, several years later in 2003, Catherine became pregnant naturally.

"At my 12-week scan the baby was fine but when I was 19 weeks they said it had had a brain haemorrhage."

The couple were told the baby they called Jack probably wouldn't survive or would be terribly disabled and they decided to terminate the pregnancy.

Catherine says: "We thought that was it but eight weeks later I fell pregnant again with Ethan. He too had a massive haemorrhage."

They were told Catherine was suffering from a rare condition called neo-natal alloimmune thrombocytopaenia (NAIT) which meant her own antibodies were destroying the babies' blood platelets and causing the bleeding. Even worse, it could happen again in any future pregnancies.

The disorder, which can result when foetal blood platelet antigens inherited from the father are different from those of the mother, is estimated to happen in around one in every 1,100 births but may be under-reported.

The couple were devastated at losing two babies, but then were given new hope from an unexpected source.

They saw a TV medical programme about a woman with a similar condition who had blood tranfusions throughout her pregnancy.

Catherine immediately telephoned the professor featured. "I didn't really expect him to ring back, but he did, the very same day. He said he was too far away but he knew someone in Bristol who could help," she says.

Catherine then got a call from the St Thomas Foetal Medical Centre in Bristol, who arranged a meeting with the couple five days later. She was told about treatment, but warned the chances of success were low.

A week later, in May last year, she was pregnant again and a very difficult and worrying seven months of treatment at Bristol and the Royal Gwent Hospital in Newport followed.

At 13 weeks tests revealed the baby had the type of platelets that Catherine's anitbodies would attack.

The blood transfusions, to increase the baby's platelet levels, had to be delivered through the umbilical cord.

"The chances of losing her were very high at that stage - they were putting platelets directly into her.

"A normal person has between 150,000 and 400,000 platelets - she had just 6,000."

Transfusions took place every seven to ten days. On one occasion the umbilical cord started to bleed and the doctor took blood from Catherine's arm and injected it directly into the baby's heart in a bid to stop the bleeding.

"It was just like a nightmare," Catherine says.

But the treatment worked. Yet at the fifth transfusion, the bleeding started again and McKenzie's heart actually stopped. The doctors then began giving the tranfusions through the baby's liver instead.

When Catherine was 30 weeks pregnant, she and Ian decided to have the baby delivered instead of letting her endure any further trauma.

She was delivered safely by Caesarean on December 6 at the Royal Gwent Hospital, weighing 3lbs 5oz.

McKenzie spent three weeks in hospital before being allowed home for the new year and is now thriving, with a healthy platelet count of more than 400,00 and weighing more than 6lbs.

The couple are naturally over the moon with their 'miracle baby' McKenzie Grace - the name McKenzie chosen because it sounded 'so strong' and Grace because it means to give thanks - and thrilled that she is coming on "in leaps and bounds."

Zoe, a pupil at Ebbw Vale Comprehensive, adores her new little sister and the couple say their family is now complete.

"Looking back I can't believe that I went through it - it just seems surreal now. She is just perfect," says Catherine.

"I would say to anyone who is considering this, that it can be done but you do need lots of support. I couldn't go through it again."

Catherine and Ian say they are extremely grateful to everyone who has helped them - including people they have never met who knitted clothes for the baby.

They want to thank everyone, from family and friends to the many health professionals at both hospitals whose care and expertise enabled them to have McKenzie, and especially Professor Peter Soothill and Tim Overton at Bristol and Royal Gwent consultant Jo Weiner.

Catherine says: "Sometimes there were six or seven people in the room during the transfusions.

"I say that most women only have one man to thank for giving them a baby - I've got about eight!"