How do you cope with chemotherapy when you know it could harm your unborn child? Sarah Bell tells Joanna Moorhead her story

As the doctor in the cancer clinic asked her to sit down so he could talk through the results of her latest tests, Sarah Bell's heart sank. Surely, she thought, it wasn't going to be more bad news - especially not today, when she didn't even have her husband, Garnet, with her. But the doctor's news was anything but bad. "The tests have turned up something new," he told her gently. "But it's not about the cancer. It's that you're expecting a baby...."

Sarah, 35, and 33-year-old Garnet had been trying for a baby for more than two years, and had almost given up hope. Days earlier, the couple had heard the devastating news that Sarah had a potentially life-threatening cancer, follicular non-Hodgkin's lymphoma (NHL). "I'd had a lump on my collarbone and thought nothing of it, but I happened to mention it to the doctor when I had flu," says Sarah. "I was making light of it - I said something like, 'It's not life-threatening, is it?' And there was this ominous silence, and I thought, oh my gosh."

She was rushed into hospital for a biopsy, which revealed the disease. And as well as the shock of having such a serious illness, Sarah also had to face the fact that the chemotherapy she needed would probably make her infertile. "It was another blow, on top of the cancer," she says. "It meant it was very unlikely that there would ever be a baby."

Now, though, less than a fortnight later and completely out of the blue, Sarah was being told she was six or seven weeks pregnant. "I was completely stunned," she says. "It was the last thing I'd expected to hear that day."

But her initial elation was soon replaced by fear. How would this longed-for baby survive a pregnancy punctuated with chemotherapy? "The doctors were honest: they said, from the start, that it would be better if we could avoid chemotherapy until after the birth. Fortunately, the lymphoma is a disease that you can take a 'wait and see' approach with, as it can be very slow-growing."

The other good news was that, once the baby was born, Sarah could be treated with a new drug - rituximab - that would greatly improve her outlook. With chemotherapy alone, patients with follicular NHL need more treatment on average every 12 months: but those who receive the new drug are likely to get four symptom-free years.

So convincing are the rituximab studies that it last week became only the second drug after herceptin to get fast-tracked by the National Institute for Health and Clinical Excellence (NICE), and now has the stamp of approval as the recommended first-line treatment for all follicular NHL patients.

Unfortunately for the Bells, Sarah's illness was not stable enough for chemotherapy to be held off until after the birth. "It wasn't that I was feeling terrible or anything - in fact, from the outset I'd never felt bad with the cancer," she says.

As the pregnancy progressed, Sarah went for tests every fortnight, each time hoping chemotherapy could be held off a little longer. But it wasn't long before these hopes were dashed. "When I got to four months, they said the masses in my lymph nodes were getting bigger, and that I did need chemotherapy. It was a very scary thing to agree to, because everyone tells you to be so careful when you're pregnant."

Chemotherapy, as Sarah knew, would mean flooding her pregnant body with dangerous chemicals - and though the doctors promised they would do everything they could to use drugs that wouldn't harm the baby, there was a risk of creating birth defects. Also, heartbreakingly, Sarah was told that if her child was a girl, she might be infertile too. "It was a terrible thing to have to think about - but the bottom line was that if I didn't survive, the baby wouldn't either."

Having to go to a cancer ward and receive chemotherapy while pregnant was, says Sarah, a searing experience. "You go along there and you see everyone looking at you and looking at your bump and thinking, oh that poor woman, she shouldn't be here while she's having a baby. You feel you're in completely the wrong place; everyone was extremely kind, but it was a very hard thing to go through." To minimise the risks, Sarah's baby was heavily monitored during the treatment, and to everyone's relief there were no discernible problems during or after the chemotherapy had been administered.

Often, says Sarah, being pregnant and having cancer at the same time felt like being pulled between two different sets of doctors. "There were the haematologists on one side talking about what I needed for the lymphoma, and there were the obstetricians on the other hand talking about what would be best for the baby. It felt like a balancing act, with me and the baby in the middle. In the end they agreed to give me four lots of chemotherapy, and then to induce the birth a month early so I could have more chemotherapy as soon as possible afterwards."

Astonishingly, Sarah not only managed to work throughout her pregnancy and cancer treatment, but also took part in one of the busiest projects of her career. She works for the Foreign Office - she'd been about to come home from an overseas posting, to Anguilla in the Caribbean, when she discovered she had cancer - and she was now heavily involved in the build-up to the July 2005 Gleneagles G8 meeting.

"It was a huge event and I really wanted to be there and to be involved in it," she remembers. "By then I was very obviously pregnant, and my colleagues were enormously supportive - but what hardly any of them knew was that I was battling cancer as well. I'm not a centre-of-attention person, though, and I didn't want to cope with all that on top of everything else going on, so I chose to keep it in the background - although my managers, of course, did know."

As soon as the G8 was out of the way the birth was induced at St Thomas's Hospital in London on 27 July last year. "The delivery room was crammed with doctors," Sarah remembers. "And the epidural didn't work properly. After a while they started talking about a caesarean, but I was determined to push her out myself. It took a bit of help from a ventouse, but I did manage it in the end. And seeing my gorgeous daughter, Toni, for the first time was the most magical experience of my life. I looked down at her and I thought, this really is my miracle child. She's been up against so much, but somehow she's managed to make it through."

The haematologists wanted to give Sarah rituximab straight away, but - knowing she couldn't take it and breastfeed - she refused. "I'd done everything they'd suggested up to that point, but this was something I felt strongly about: I knew I wanted to breastfeed," she says. "And I knew that even just a few days would give Toni a great start, and help us to bond. So I said they'd have to delay the drugs - and in the end we agreed that I could have nine days to breastfeed, and on day 10 it would be back to chemo and on to rituximab. Giving Toni her final breastfeed was very emotional, but I've always tried to think about what I have got, rather than what I haven't. So I thought, at least she's had breast milk for nine days; it's better than no days at all."

Returning to the chemotherapy ward with Toni was as difficult, says Sarah, as going with a bump. But now, more than a year on, she's back at her desk at the FO and is loving life with Toni and Garnet. And, thanks to rituximab, it might not be until Toni is at school that she'll need to visit the chemotherapy ward again. "For patients like Sarah, this really is a very significant drug," says Dr Graham Jackson, lymphoma expert and consultant haematologist at the Royal Victoria Infirmary in Newcastle. "It targets the tumour cells directly, so it has far fewer side-effects than conventional chemotherapy. And combined with chemotherapy, as it was for Sarah, it works extremely well.

"Lymphoma is a real Cinderella cancer, because despite being quite common it's not one that gets a lot of attention - and having to keep going back for chemotherapy isn't good for anyone's life. Being able to have a treatment that keeps the cancer at bay for years, as has hopefully happened, makes a big difference to a patient's quality of life."

Sarah couldn't agree more. "Sometimes I can't believe what I went through," she admits. "I know the cancer will come back - but what matters most to me is that, for the moment, I can put it behind me, and enjoy life with Toni and as a mum."

What exactly is non-Hodgkin's lymphoma?

* Non-Hodgkin's lymphoma (NHL) is a cancer of the immune system, and affects the white blood cells, or lymphocytes, which tend to collect in the lymph nodes, making them lumpy and swollen

* Follicular NHL, the type Sarah suffers from, accounts for around four in ten cases of NHL. It's a slow-growing form of cancer but also an incurable one - though it is more controllable than many other cancers, and sufferers often survive many years or even decades with treatment

* Rituximab (also known as MabThera) has been around for five years, but has mainly been used as a second-line treatment option for patients who have already had several rounds of chemotherapy. The new NICE ruling means patients like Sarah can benefit from longer spells of remission from the outset, rather than having to endure more regular doses of chemotherapy.

* NHL is an increasingly common form of cancer; around 60,000 people in the UK have the disease, and 9,200 people are diagnosed with it each year. It has increased by 80 per cent since the early 1970s, and is rising by 3-7 per cent annually.