Rowan Pelling: So would you call me a murderer?

I didn't need to see the pictures of a 12-week foetus "walking" in the womb to remind me that, even at this early stage of life, there's a pulsing bud of a person emerging. As many women can tell you, from the moment you suspect conception, there's a strange sensation of being haunted from within.

This awareness of surging life is true whether a pregnancy is wanted or not. So I can't share the view of the anti-abortion lobby that publication of these photos means, as Nuala Scarisbrick of the charity Life puts it: "That everyone will see that abortion is as barbaric as killing a born baby." The truth is that, while most women already think abortion is pretty barbaric - no one takes a jolly jaunt to the Marie Stopes clinic - they don't tend to believe it's as barbaric as being forced to act as a human incubator against your will or circumstances. And because most women aren't insane, they don't think the removal of a non-sentient, early-term foetus is morally equivalent to infanticide.

The ethics of reproduction may currently be an uncomfortably compromised grey area, but consider the alternatives. In a week when the philosopher Peter Singer has incensed people for reasoning that there is no moral difference between aborting a baby on the grounds of a chronic disability and administering a lethal injection to the same child at birth, we should perhaps apply the same harsh logic to the pro-life lobby. If they believe that all life is equally sacrosanct from the moment of conception, then it is equally abhorrent to abort a chronically disabled foetus as a healthy one. And that makes me a murderer.

In spring last year I discovered that I was pregnant and decided, at 11 weeks, to pay for the detailed nuchal scan. As the scan proceeded, I could not help but notice an ominous silence and the operator's frowns. Tears were slipping down my cheeks long before she said that there were "some anomalies". I was referred to Addenbrooke's hospital the same day, waiting with my husband among hordes of beaming parents-to-be for the solicitous consultant.

Again the shrimp of a foetus was summoned up on a dark monitor, its tiny fingers and beating heart so cruelly suggestive of life in all its rich potential. The doctor said he thought there was a more than 50 per cent chance that the baby had a severe disorder, and suggested carrying out a chorionic villus sampling (CVS) test, in which a sample of tissue is taken from the placenta.

We waited for the results already knowing we didn't want to continue with a pregnancy where the odds were so heavily stacked against us. In the event, the CVS results showed that the foetus had Patau syndrome, a fatal congenital disorder affecting the major organs. This was devastating news and yet, curiously, something of a relief. For us there would be no agonising over whether to end the life of a child with Down's syndrome or a severe heart defect, a decision that would have proved particularly gruelling as my husband's sister was severely handicapped with Down's, living only a few years, and the wonderful daughter of our dearest friend in Cambridge has endured years of surgery due to a congenital heart condition. Perhaps these very facts meant that we were only too aware of the unbearable toll of parental love under such circumstances.

I had a guilt-free termination, though not one free of heartache, enjoying the moral luxury of sympathetic support from medics, friends and family. And the story ends happily with the subsequent uncomplicated pregnancy that resulted in the birth of my son two months ago.

But it's galvanising to think that, if the pro-life lobby had their way, there would be no nuchal scans, no CVS, no terminations. I would have carried my poor blighted baby to term and then watched it die slowly in front of me. And those carrying healthy but unwanted foetuses would be prescribed enforced adoption, as though the psychological trauma of pregnancy and childbirth were equivalent to finding a new home for a kitten. In view of this, most people would rather accept the messiness of a world where women have sovereignty over their own wombs.