Eight years ago, when I was 32, I went for a routine scan. I was 20 weeks pregnant, and looking forward to bringing home the first grainy photo of our much wanted second baby. I can only recall snippets of the conversation the consultant and radiographer had as I lay on the bed. Various "anomalies" in my baby were pointed out on the screen, and discussed. They spoke to each other, not to me, and most of what they said I couldn't understand. "Neural tube defect" meant nothing; spina bifida did. EastEnders had just run a storyline in which a character had terminated her pregnancy following a similar diagnosis. What I remember clearly is the utter desolation I felt as the future I had mapped out was left in tatters.

A consultant talked my partner and me through the best- and worst-case prognoses for our baby, and set out our options, one of which was termination. Had I chosen to continue with the pregnancy, I was told that, at best, our child would have a range of handicaps that would restrict mobility and cause ongoing bladder and bowel problems, and at worst, the outcome would be paralysis and permanent brain damage - hydrocephalus (water on the brain) was also clearly visible from the scan. In this instance the chances of survival beyond early childhood would be slim and quality of life seriously impaired.

Would it have been easier if we had been told there was no compatibility with life? The short answer is no. This wasn't about having a "perfect baby", but about making the right decision for our unborn child, myself and our family. The decision was probably the hardest I will ever make, but one I remain convinced was right.

Over the 40 years since the Abortion Act became law, repeated attempts have been made both to repeal and restrict it, and in recent years late abortion has been systematically targeted. Objections to late abortion centre on foetal viability and the brutal mechanics of the process - medical induction, foeticide, labour and birth - cited by anti-abortionists as reason enough for reform. Although the Commons science and technology select committee this week said that the 24-week limit should not be reduced because the survival rate of children born below that age is still extremely low - a view upheld by the British Medical Association, the Royal College of Obstetricians and Gynaecologists and the Royal College of Nursing - ultrasound images of "walking babies" in the womb continue to fuel a groundswell of opinion favouring a reduction in the legal limit. In one recent survey, 68% of people thought the limit should be reduced to 13 weeks.

Ongoing scaremongering by anti-abortion groups - in the form of stories of botched abortions (babies being born alive) and allegations that terminations are routinely performed for "trivial" medical conditions, such as cleft palates - is rife. There is pressure from certain quarters to come up with a "tick list" of foetal abnormalities that would be seen as justifying late abortion - even though a study by the Centre for Family Research, University of Cambridge, looking into the decision-making experiences of foetal medicine professionals, concluded that such a list would be both "unworkable" and "unhelpful". Meanwhile, emotive terminology such as "partial birth" and "eugenics" keep the debate on late termination focused on foetal viability and rights.

And throughout all this, one crucial voice has been overlooked: that of the women who have excercised their right to choose, and have had late abortions.

Our experiences can be extremely upsetting, so perhaps it is not surprising that people don't want to hear them. Julie (not her real name) had a termination at 36 weeks. A 20-week scan indicated there might be some complications but these were attributed to a newly installed ultrasound machine. It was only a further scan, at 32 weeks, that detected a serious medical condition in her unborn child.

"It was like entering a black hole," she recalls. "The radiographer wasn't prepared to discuss it, and I then had to wait for three hours in a room full of other happily fat pregnant women for a consultant. The consultant also refused to say anything and I was told I would have to wait until after the weekend to see a specialist."

Julie overheard medical staff openly discussing her situation before being subjected to a further scan with around half a dozen people in the room, including several students. "It was as if I wasn't there," she says. "The consultant was brutal, likening babies in special care units to 'little rats tied to machines'." Three weeks later, when the severity of her baby's condition was eventually confirmed, Julie had a termination.

Stories like Julie's and mine are not often told. The silence is partly because late abortion remains taboo; even those who are "pro-choice" often feel uncomfortable being seen to support a woman's right to choose this. About three months after my own abortion, I remember publicly - and loudly - berating a group of close female friends who had avoided the subject. Their defence was that they were taking their lead from me - that they thought I would have broached it, had I wanted to discuss it - but I felt they were deliberately ignoring what had happened. Meanwhile, I found myself being selective with the truth with everyone other than immediate family and my closest friends, not wanting (or able to cope with) being judged. Allowing people to believe that I had "lost" the baby through a late miscarriage was easier than having to justify my actions. The guilt I felt over those first few months, despite my conviction that what I did was right, was immense.

Over time, I felt more willing to talk about what I had been through and discuss the decision I had made. It wasn't always easy, and people's reactions were not always predictable; someone I had known for a long time, and counted as a friend, was so shocked that our friendship eventually ended, whereas a deeply religious colleague, to whom I had been dreading telling the truth, was incredibly sympathetic and supportive.

But it is not only other people's disquiet that makes late abortion difficult to discuss. Beth, who terminated a pregnancy at 24 weeks after antenatal screening picked up a condition in her baby that was incompatibile with life, acknowledges her own difficulties in coming to terms with her decision. "As a Christian, [abortion] challenged my beliefs greatly," she says. "I had studied eugenics and was working at that time with adults and children with learning difficulties. I felt I was going against them and everything I worked for."

"It has taken me three years to be open with some of my closest friends, although recently I have been telling people." Beth does not regret her decision, though: "I'm proud of the decision I made out of love for my unborn baby - and not a day goes past when I don't think of him."

Such ambivalence was common among the women I spoke to; while talking candidly about their decisions, they also mentioned some associated doubt and guilt, which was made more acute by the wider societal disapproval. Marketing manager Debby Cooper, 30, had an abortion four years ago. She believed strongly that no one had the right to judge her, and so was open about the fact that she had terminated her pregnancy at 21 weeks. Nevertheless, she still felt she had to justify her "choice".

"I could never just say, 'My baby had brain abnormalities and I had a termination at 21 weeks,' " she confides, "I always had to go on to explain that the baby would have died within a few hours of his birth.

"Mainly people were very supportive. I wanted someone to argue, I wanted someone to challenge me so I could justify why I did it." Debby even logged on to anti-abortion forums to try to "bait" someone into an argument as a way of assuaging her own guilt, although she found "pro-lifers" surprisingly tolerant. "I never met anyone who totally disagreed with what I'd done. They may not have done it themselves, but they couldn't disagree."

It seems that, when confronted with the reality of an individual's experience of late-term abortion of a profoundly disabled foetus, even many "pro-lifers" find it hard to condemn the woman. But while a significant number of late-term abortions are carried out following a diagnosis of abnormality, not all are. Many people - and even some medical professionals - differentiate between these and so called "social abortions", a tag that angers pro-choice campaigners.

"One of the concerns is that as soon as you start saying that disability is a separate issue there is a danger of going down a slippery slope," says Anne Quesney of the national pro-choice organisation, Abortion Rights. "Access to late abortion is a right that should be upheld for whatever reason."

Women who have experienced this type of late-stage abortion speak of disapproval even from some of the medical professionals who treat them. Marion, who had a termination at 24 weeks in the 1970s, received little in the way of sympathy or support. She was 19 at the time. Thirty years on, she still remembers the unfriendly manner of one of the doctors and open hostility from an attending nurse. "They made me feel horrible," she says. "Nobody explained what would happen to me and in those days you didn't ask questions. I wish I'd had a lot more support, just in terms of what was going to happen." Marion didn't know she was pregnant until 16 weeks, and then had to wait weeks for an appointment. "It was my first pregnancy and I was very young."

With access to early home pregnancy tests now readily available, and sex education part of the national curriculum, it may be hard for some people to understand why a woman wouldn't realise she was pregnant until four or five months down the line, yet a study by Marie Stopes International (MSI) in 2004, examining why women present late for abortion, found it to be one of the primary reasons behind many later-term abortions in private clinics - often because early signs of pregnancy are masked by the onset of menopause or the irregularities of teenage menstrual cycles.

This is what happened to Zoe, who, at the time, was 17 years old and studying for her A-levels. Showing no visible signs of pregnancy or any related symptoms, Zoe, who was using contraception, was reassured by her GP that she was not pregnant, despite having missed several periods. However, an early test taken by her GP turned out to be a "false negative". Zoe's pregnancy was only confirmed at 19 weeks, on a return visit.

"The doctor had done such a good job of reassuring me first time around," she says, "that I didn't think I could be." Aside from her GP (who expressed some guilt about the late diagnosis), Zoe had little in the way of support from medical professionals during the termination process, which took place two weeks later. "It was just this hideous situation where the doctors and most of the nurses were hostile and judging me," she recalls. Zoe cites a midwife asking her if "she had thought about contraception", despite the fact that at the time she was on the pill.

Despite her experience in the hospital afterwards - "I couldn't stop screaming and was told to be quiet" - Zoe believes the long-term effect of her decision has been a positive one. "I took everything for granted before then," she says. "It's made me make the most of situations - like when I didn't feel like revising, a voice in my head would say, 'Well, you might as well have had that other life if you're not going to make the most of your opportunities.'

"My life would have taken an entirely different course and I have no idea how I'd have coped with that or who I would now be."

When I had my abortion, I was lucky to recieve very good care. So did Carrie McMillan, who was 32 when she had an abortion at 22 weeks after a diagnostic scan revealed serious problems. She describes the medical staff who treated her during her late abortion two years ago as "absolutely brilliant". She recalls the moment the consultant delivered the news. "We couldn't believe something was seriously wrong, but then the consultant said that in his opinion, given the severity of our daughter's condition, she was unlikely to survive."

If a woman is more than 13 weeks pregnant, labour has to be induced, and normally takes less than six hours. Carrie's labour was much longer because the baby was breech. Afterwards, she says, "We stayed with her for a few hours and the midwife left a camera and dressed her in a premature nappy and cardigan and filled in the card you get given with other births." When Carrie felt ready to go to the ward, "The midwife said she would stay with [the baby] for the rest of her shift; she acted as if she was an important baby, which she was to me." Despite the trauma of the birth, Carrie says she is glad she went through labour as it helped her to come to terms with what had happened. When she got pregnant again only months later, she was once again impressed by the care she received. She was offered numerous scans as reassurance - unnecessary, in the event, as her daughter, Kizzy, "scared the crap" out of her by arriving two months early.

Anecdotally, it seems that women like Zoe who have late abortions on so-called social grounds are more likely to be treated as undeserving of compassion when in hospital than those of us who terminate because of foetal disability. Certainly, there is a huge variation in the standard of medical care and treatment received by women during and after late abortions. Christoph Lees, a consultant in obstetrics and foetal medicine, says that this is a "Cinderella area" of medicine that could benefit from proper national training standards. "Care in these situations is well-meaning but haphazard," he allows. "It would be nice to make it more consistent. It doesn't take huge resources to get it right, but it probably takes more thought."

Late-term abortion remains rare - 89% of all abortions in the UK are carried out at 12 weeks or below; only 1.5% take place after 20 weeks. The process can be physically and emotionally traumatic, and is never undertaken lightly. Those of us who have had late abortions have felt the force of moral outrage - we know that people who have never been in a situation like ours can be all too easily persuaded that the law should change. This is why it is important that our stories are heard.