Can a foetus feel pain?

一月 10, 1997

Research into what foetuses feel is all too often prey to distortion by political propagandists, argues Sara Abdulla.

Modern medicine throws up just as many questions as it does answers. In few other fields are the questions so fraught with implications as in foetal and neonatal medicine. The ability of surgeons to perform transfusions and even, in the US, surgery on the foetus has raised a query of enormous clinical and ethical consequence: how much, if anything, can a foetus feel during these procedures? If indeed the foetus does feel pain, what effect will this have on its future development? If surgeons are to give pain relief to the foetus will this cause greater physical and mental damage than pain or stress?

Unfortunately, while trying honestly to answer these finely balanced questions, researchers have found themselves at the centre of the political debate surrounding abortion. According to John Wyatt, consultant neonatal paediatrician at University College London Hospital and member of the Rawlinson Commission of Enquiry into Human Foetal Sentience, anxiety is now stifling research. He worries that "no responsible scientist or clinician can publish work in this area without a certain degree of trepidation that it will be seized upon by spin doctors and propagandists from both sides of the abortion debate".

This is a well-founded fear. Already, controversy about whether or not the foetus feels pain while it is being aborted has supplemented the moral arguments Pro-Life campaigners have traditionally used to try to restrict women's ability to obtain legal abortions. Later this month a bill, sponsored by a Conservative MP, and aimed at tightening up the 1967 Abortion Act, will receive its second reading.

Why do we feel pain? When an adult is pricked in the finger by a needle, receptors in the skin set off an electrical signal. In the thalamus, an egg-shaped organ in the centre of the brain, such signals are sorted, amplified and sent on to the cortex. Only when the signal reaches the cortex are its source and nature registered by the brain - "ouch, my finger!"

But pain is rarely that simple, even in adults. Subjective factors such as expectation, memory, and dismay add to the quality and duration of the sensation. In a Department of Health review of current scientific knowledge on foetal pain Maria Fitzgerald of University College London concluded that thalmo-cortical connections are essential for pain perception. These connections begin to form in the 17th week of life and are more or less in place by the 26th week.

But many clinicians and philosophers dispute the assertion that pain is just a question of physiology and anatomy. Stuart Derbyshire of Hope Hospital, Salford believes suffering due to pain is predicated upon consciousness. In an article in a special "Education and Debate" issue of the British Medical Journal last September he said that "foetal pain is a misnomer at any stage of foetal development. Whether the foetus feels pain hinges not on its biological development but on its conscious development. Unless it can be shown that the foetus has a conscious appreciation of pain then its responses must still, essentially, be reflex."

The circuitry responsible for the withdrawal reflex is in the spinal cord. The reflex may be seen in a decapitated frog or a lightly anaesthetised adult human and in the foetus as early as seven weeks arising from a touch on the lips. Organised physical and hormonal foetal responses to noxious stimuli, such as a needle prick to the abdomen followed by a blood transfusion, are currently being investigated by Vivette Glover and Nicholas Fisk of Queen Charlotte's and Chelsea Hospital, London. They have shown that foetuses undergoing blood transfusions show classic hormonal stress responses - increased blood flow to the brain as early as 18 weeks and increased cortisol, a hormone which stabilises blood pressure and body water, at around 23 weeks. However, stress does not equal distress. A fully anaesthetised adult patient undergoing major surgery does and should respond in exactly the same way though clearly feeling no pain.

So maybe the question for the clinician ought not to be does the foetus feel pain but does intra-uterine stress have a detrimental effect on the physical or psychological development of the foetus or child? Evidence that early exposure to noxious stimuli can have adverse effects on future neural development is increasing. But there is a further complicating factor, as Lewis Wolpert pointed out in a recent Ciba Foundation meeting on the subject "Can the Foetus Suffer". "In a cost/benefit analysis how do the effects of stress compare to the impact of administering potent anaesthetics - often potentially addictive opium derivatives - to the foetus?" asked Wolpert. At present no one knows but Glover believes we "should give the foetus the benefit of the doubt". Accordingly surgeons at Queen Charlotte's and Chelsea Hospital now use the anaesthetic Fentanyl when operating on foetuses of 23 weeks or more.

There is still a huge amount of work to be done to minimise foetal stress and distress, if it exists. Infants who have undergone intra-uterine operations and/or received analgesics should be monitored as they grow up so that medium- and long-term effects of these procedures can be known, understood and managed.

But while trying to fine-tune these rare but lifesaving procedures researchers are being unwillingly sucked into wider, ethical, debates. Glover and Fisk have been criticised by their peers for changing their clinical practice on the basis of nascent research. "This is emotion-based medicine rather than evidence-based medicine," said Charles Rodeck, an obstetrician at London's University College Hospital.

And although the scientific jury is still, very clearly, out, the Pro-Life lobby has already hijacked the little data there is to revive its flagging campaign. Capitalising on last summer's public outcry about the destruction of 3,300 IVF embryos and the selective abortion of a healthy twin, the all-party Parliamentary Pro-Life Group recently wheeled "foetal pain" centre stage with a pseudo-scientific document entitled "Foetal Sentience". In it a group of authors and advisers, not one of whom has published in neuroanatomy or physiology, state that "the anatomical structures subserving the appreciation of pain are present and functional before the tenth week of intra-uterine life".

In light of the fact that not one of the panel of seven experts writing in the aforementioned BMJ issue gave a watershed of less than 23 weeks for anything higher than reflex reactions to pain, David Paintin, director of the Birth Control Trust and emeritus reader in obstetrics and gynaecology at Imperial College of Medicine, St Mary's Hospital, condemns this "tenth-week" claim as "ludicrous". "Whether or not the foetus feels pain is irrelevant to the abortion debate, either you believe that the foetus deserves the same fully fledged legal rights as the new-born or you don't," he says. "Frustrated that they have difficulty converting others to their beliefs with legitimate moral arguments, Pro-Life campaigners are now trying to arouse public opposition to legal abortion by suggesting that the foetus might feel pain during the process."

And it is working: "The Foetal Sentience Report has moved the debate about the humanity of the unborn child firmly up the public, parliamentary and political agenda," says MP Anne Winterton, chairman of the all-party Parliamentary Pro-Life Group. Leaders in the Daily Mail, the Mail on Sunday, the Daily Telegraph and Sunday Telegraph have called for changes in abortion legislation and there is barely a journalist left who doesn't refer to the foetus as the "unborn child". As a result, David Amess, Conservative MP for Basildon, is presenting a bill on January 24 to tighten up section 1(1) of the Abortion Act of 1967 under which 97 per cent of all abortions are carried out.

Ann Furedi, director of the Birth Control Trust, is more concerned about the psychological impact that this kind of speculation could have on women: 89 per cent of aborted foetuses are less than 12 weeks old, only 1.2 per cent of abortions are carried out when the mother is above 20 weeks pregnant, usually because of foetal abnormality. "These are wanted pregnancies, often of older women who have formed a relationship with their potential child. For them a termination is extremely distressing and to exacerbate this for political ends is reprehensible," she says.

Sara Abdulla is science writer in residence at the CIBA Foundation.

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