For the ever-increasing number of couples whose passage to parenthood is difficult, those risks are all too real. As more and more women delay starting a family -- the average age of a first-time mum in Ireland is now 31 -- the demand for IVF and other fertility treatments, with all the attendant complications, has also grown. Desperate for a baby and longing to start a family of their own, couples can find themselves facing some very tough choices.

To date, Siobhan Tobin (30) and her husband Thomas (34) have spent almost €30,000 trying to conceive. Already proud parents to Thomas and Jamie, their gorgeous 10-year-old twin boys, two years ago, Siobhan and Thomas decided to try for more children. Within weeks of trying, Siobhan fell pregnant -- once again, with twins. But just two months later, she miscarried. "It was devastating. It was the worst feeling I've ever had," she says.

But worse was to come. Following two D&Cs performed after the miscarriage, Siobhan developed scar tissue in her womb -- a common complication known as Asherman's Syndrome -- which left her struggling to conceive again. The months to come would be an exhausting emotional rollercoaster for the Tobins, from the initial confusion and distress of not knowing what was wrong to the heartache of realising they were unlikely to conceive naturally again.

In their bid to tackle the problem, they've visited doctor after doctor, from the plush private rooms of Harley Street in London to a Hamburg clinic, to hospitals here in Ireland. Now they have been offered new hope by a top UK specialist who believes he can help the couple get pregnant again.

Today, Siobhan, having twice had surgery to repair the lining of her womb, continues to take expensive hormone treatment.

The financial burden has become part and parcel of everyday life.

Siobhan, a beauty therapist, has taken on a second job to pay the bills while Thomas, a courier, regularly puts in extra hours. Most of their savings have been poured into the struggle to conceive while at the same time paying a mortgage and bringing up the twins. With all their extra cash spent on medical bills, holidays, for now, are a thing of the past.

'I know that all of this seems mad, especially for someone who already has two children," Siobhan admits. "But the way I see it is this: where do you draw the line? Do you say, 'yes, I will spend €15,000 on this, but not €15,500? Because you never know how far away you are from success. You could be just one step away from getting pregnant.

"If I had to borrow money, I would. I will keep going until the doctors tell me that I can't go on any more. And the money will have to be found somewhere."

None of this is a surprise to Helen Browne, the founder of the National Infertility Support and Information Group. Debt is a regular feature of phonecalls to the group's helpline. With one cycle of IVF costing around €5,000, and fertility drugs costing another couple of thousand on top of that, many couples find themselves with some difficult financial decisions to make.

"Some couples extend their mortgage, some get rid of the car. Some get help from their families, and I have heard of people who have cashed in an insurance policy. But, after all, people take out loans to go to college. Why not to have a baby?"

Indeed, Helen did exactly that herself. She and her husband completed several rounds of IVF, and found assorted ways to foot the bills. "We sold a car, cashed in an insurance policy and borrowed -- but we could still pay our mortgage and eat. You sacrifice some things and I was happy to do so."

The lengths to which women will go to realise their goal of getting pregnant can prove problematic for the clinics treating the couples, top UK fertility doctor Professor Sammy Lee acknowledged recently.

"The quest to have children can become a vortex that gets faster and faster and sucks people in," he says.

"Women will sell everything and anything to have the treatment if they are short of funds. They will risk their lives, there's no doubt about it."

Lee says he has even treated women who had risked their own well-being by delaying chemotherapy in order to complete IVF.

The health risks also play on Siobhan Tobin's mind. While recent studies suggest fertility treatments are unlikely to lead to an increased risk of cancer, not all are convinced. Before she died in 2003, aged 41, from breast cancer, Sarah Parkinson, wife of TV comic Paul Merton, blamed her illness on IVF.

"I know that taking hormones increases the risk of cancer," says Siobhan. "And because of the drugs I'm taking I also have to take aspirin every day to reduce the risk of thrombosis. But the surgery I've had won't work unless I take the hormones. I don't think about the risks, because I want this pregnancy so badly. I think of it like this: I don't drink or smoke -- so I am probably healthier than the average person this age. And I know that pregnancy is a risky business anyway."

For Siobhan and Thomas, the whole experience has brought them closer together, but there's no denying that it's been a strain.

"This is the first problem I've had that Thomas has not been able to fix," says Siobhan. "Our relationship is very much like that: if there is something wrong he fixes it. He can't fix this. He finds that very hard, and it is for me too. I am a woman that can't have a baby -- and that very fact feels wrong."

No matter how distressing it is, Professor Lee suggests that clinics should be more willing to tell couples when 'enough is enough' -- financially, physically, and mentally.

"It is hard for couples to accept that they need to stop treatment", says Joan Hamilton, head counsellor at the Rotunda's HARI unit. Rituals, like lighting a candle or writing a letter to an unborn child, can help.

"We get couples to focus on who they are outside of the desire to have children -- are they going to have other hobbies or focus on other things, like work for instance. We help them to learn to go on to the next phase."

In the end, after several unsuccessful attempts, Helen Browne and her husband gave up. "It was very difficult to stop," she admits, "but we were exhausted, both physically and financially."

But for the Tobins, their fight continues.

"If I get to that stage when the doctors tell me they can't do any more, I will be able to accept it," says Siobhan.

"But only when I know I have done everything humanly possible to conceive. And then I will have to accept that this was not meant to be."