As part of a series of articles BBC News Online reporter Jane Elliott looks behind the scenes of the NHS.
Oscar is the apple of his mother's eye
This week she talks to a woman about the difficult health dilemma she faced when she and her husband decided to start a family.
Elizabeth Lee is the proud mother of a six-month-old baby boy.
Oscar is beautiful and the apple of her eye, but the 30-year-old mother knows the decision to have him could have cost her dearly.
For Elizabeth has cystic fibrosis (CF) and needs regular hospital treatment to keep her lung function as high as possible.
At the moment her lungs have slipped to just under a quarter of their capacity and Elizabeth has been put on the transplant list, but she says having the child of her dreams has made all her health sacrifices worthwhile.
"I had always wanted a baby, ever since I was five years old.
"I just could not imagine never having a baby. It did not seem right.
"I have no regrets about the decision I made. If somebody had said you can have five minutes of this time with Oscar or 20 years of health without him then I would chose the five minutes with him every time.
"He has made me so happy."
Because of her health problems, Elizabeth and her husband Michael decided to try as early as possible for a child.
But after five years of trying and two rounds of fertility treatment she showed no sign of becoming pregnant.
"Oscar is my little miracle baby. We had been through fertility treatment twice and we were thinking of going through it again when I found I was pregnant at a check-up."
Because Elizabeth had been preparing for some time to have a child she had ensured her lung capacity was as high as possible.
"Because we started trying for a baby when I was 25 I was very fit and my lung function was working at 75% of its capacity.
"The pregnancy was brilliant, I found that all my arthritis, which I also have, disappeared.
"I was in hospital from three months onwards for safety reasons though. I live on the Isle of Sheppey and my local hospital wanted me nearer the specialist centre.
"The pregnancy went really well and I felt good.
"I just bloomed even though I had nausea all the way through the pregnancy I did not feel ill."
Towards the end of the pregnancy Elizabeth's lung function dropped to just a quarter of capacity, but she said she still felt very well.
But at 32 weeks of pregnancy she was whisked in for an emergency caesarean when Elizabeth had an adverse reaction to a drug and her baby stopped moving.
Although Oscar was eight weeks premature and weighed just 3lb 2oz he was a healthy baby.
He had a little jaundice and needed to spend eight weeks in special care.
Elizabeth though took a turn for the worst and was admitted with heart problems.
Eventually the pair, who had both been treated in separate hospitals, were reunited and allowed to go home.
But after three months together Elizabeth started to get worse again and needed to be readmitted. Doctors discovered a bug that had been harbouring in her body from before the birth was causing her lung function to decline.
"The bug was already there, but having the baby caused it to surface.
"I have to keep coming back into hospital and when I am in here I do miss Oscar terribly, but my Mum brings him in to see me."
Oscar is thriving
Elizabeth loves her role as a mother to baby Oscar, but she knows that without the transplant she is living on borrowed time
"If I don't get the transplant I probably will die.
"I could catch a cold next week and it would take my lung function down and that would be it.
"It is a huge concern of mine.
"I cannot pick Oscar up at the moment because it is too much of a strain on my lungs.
"But if I get my transplant I will have 100% lung function and will be able to run around with him."
Elizabeth has no regrets about choosing motherhood, despite the toll it has taken on her health.
"I have no regrets and I would not change anything. But I would not have another baby - Oscar is too precious for me to risk my health."
Margaret Hodson, professor of respiratory medicine, said it was vital that CF patients considering pregnancy consult their doctor first, as Elizabeth did, to assess the risks both to their own health and that of any child.
She said that a simple test would show whether the baby would be at risk of inheriting CF.
Doctors would also assess the mother's health.
Professor Hodson said women generally fall into three groups - those whose lung function would be temporarily affected by pregnancy but would then recover, those who would spend time in hospital and thirdly those for whom a pregnancy would represent a serious risk of death.
"For those women we strongly advise them not to get pregnant," she said.
Professor Hodson said that although some women might suffer a deterioration in lung function during pregnancy, that is usually reversible.
"One should bear in mind that if you take a group of men or non-pregnant ladies they too could suffer a sudden deterioration of lung function.
"So a pregnant lady's lung function deterioration may be pregnancy related or it may not."
She said that women would also be advised to consider whether there would be another adult to help them care for the child if they were to spend time in hospital.
The Cystic Fibrosis Trust produces leaflets for women with CF considering pregnancy.