So, can a fetus feel pain?

A new study showing that premature babies launch a ‘brain response’ following a heel lance is cited as evidence that fetuses feel pain. One expert begs to differ.

Stuart Derbyshire

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A recent paper in the Journal of Neuroscience has demonstrated that very premature babies, born from about 25 weeks’ gestation, can launch a brain response following a heel lance (1).

The brain response involved the redistribution of blood to the primary sensory region, a key region during pain experience in adults (2), and so is unlikely to be a simple generalised reflex. Speaking to BBC News, Professor Maria Fitzgerald, the senior author on the paper, said these findings prove the baby can ‘feel true pain’ (3). In contrast, in a review published in the British Medical Journal last week (4), I argue that the case for neonatal and fetal pain may be supported by biological developments known to have occurred by around 25 weeks’ gestation, but it is emphatically not supported by psychological developments that will have occurred by that stage.

There is a difference between the biological response to damaging injury and the psychological experience of pain. As Fitzgerald herself very eloquently argued during a meeting on late abortion last year, when someone hits their hand with a hammer they say that the pain is in their hand but, of course, the pain is actually in their mind (5). To insist on that distinction every time somebody complained of pain would be pedantic and pointless; but the distinction is absolutely vital if we are to understand the subjectivity of pain and its development.

There can be no doubt that there is a minimal biological system that is necessary for pain experience, as demonstrated by people lacking certain physiological receptors who remain insensitive to injury throughout their, usually short, lives (6). Generally speaking, it is largely agreed that the necessary system for pain includes a complete link from the periphery (skin) to the cortex (brain), and Fitzgerald’s work demonstrates that this link is both complete and functional from at least 25 weeks’ gestation. But while this system is necessary for pain, it is not sufficient; there is more to the experience of pain than linking up brain and skin.

To believe that the biological system for pain is both necessary and sufficient is to believe that the pain experience itself is coded directly into the biological system and is therefore an inherent quality of life (7). This view dismisses psychological development as an irrelevancy to pain experience, which might seem uncontroversial given the seemingly automatic and effortless pain experience that follows most injuries. The problem is that this view stems from our unique perspective as beings with subjectivity who struggle to conceive of life without the trappings of awareness. We generally fail to reflect upon the content of that awareness and the psychological constructs that make it possible.

No experience can exist without it having some content and without it having some independent existence in the experiencer’s mind (8). Discriminating the various objects within the world requires a system of labelling that can allow independent manipulation of those objects. It is difficult to see the wood for the trees if you have no conception of wood or tree and I can’t simply decide all by myself that a tree is a tree and wood is wood without someone confirming that thought. After all, the tree might be a bush, or a building, or a cloud, or anything – how would I know without an available subjectively aware being to set me straight on the specifics of wood and trees?

Becoming aware of the elements of the world, therefore, is vitally dependent upon input from another human being, usually a parent or other primary caregiver (8, 9). But for this input to be effective, the infant has to be able to direct their attention towards one object over another and hold the details of that object in memory. It is no good mum telling baby ‘this is a tree’ if baby is looking at the sky. And the information is not going to be useful if it is lost as soon as it is said. Babies seem inherently good at directing their attention towards faces straight from birth but other objects take time to be observed. The earliest age at which a representational type of memory, where objects or thoughts are held in mind for extended periods of time, becomes apparent is about two months.

It seems reasonable, therefore, to suggest that subjective awareness of objects starts with the interaction of parent and infant alongside biological developments that make psychological capabilities, such as memory, possible. What is true of objects is also true of emotions and pain. Subjective experience of pain cannot be parceled off as some sort of special function that has inherent completeness – when subjectivity is unavailable, experience is non-existent; but once subjectivity has developed, experience is all-consuming. This is why it can seem so strange to be arguing against the experience of pain in fetuses or neonates. For us, pain is private, effortless and immediate but just because it is private and effortless now doesn’t mean it has always been that way. In the first instance pain has to be discriminated from the other information bombarding our sensory system; it has to be discriminated from colour and sound, and other feelings such as anger and hunger. And this discrimination involves a psychological development that is yet to occur.

None of this means we can or should be wantonly dismissive of the life of neonates or fetuses. The termination of life, including fetal life, is properly decided according to much more important principles than the question of pain. Similarly, parents, and those about to be parents, can’t stop worrying about hurting their children just because there is a period during which pain experience is not possible. Prevention of harm involves an awful lot more than the mere avoidance of pain.

It also does not mean that surgery or other invasive procedures can be performed on neonates without adequate analgesia or anesthesia. There have been multiple studies demonstrating that proper analgesia and anesthesia prevent major complications, including death, in the neonate (10). Regardless of the absence of pain, anesthesia and analgesia should remain normal practice when performing invasive surgery or other procedures on babies.

But it does mean that efforts to prevent abortion because of fetal pain, or to introduce procedures to alleviate fetal pain, are unwarranted and should be blocked (11). While pedanticism about pain and what it means to be subjective is generally pointless, and would be irritating, for parents and other caregivers, it is absolutely vital for medical science to be pedantic about the details. If we are not, then we run the risk of recommending procedures that are without clinical foundation and we will fail in the aim of providing an understanding of subjectivity in general and pain in particular.

Stuart Derbyshire is a senior lecturer in the School of Psychology at the University of Birmingham, England.

(1) Rebeccah Slater, Anne Cantarella, Shiromi Gallella, Alan Worley, Stewart Boyd, Judith Meek, Maria Fitzgerald. Cortical Pain Responses in Human Infants, Journal of Neuroscience, April 5 2006, 26(14):3662-3666

(2) Stuart Derbyshire, Exploring the pain “neuromatrix”, Curr Rev Pain 2000;4(6):467-477

(3) Premature babies ‘feel true pain’, BBC News, 4 April 2006

(4) Stuart Derbyshire. Can fetuses feel pain?, BMJ 2006 Apr 15;332:909-912

(5) Late Abortion – A review of the evidence, 27 January 2005, Boothroyd room, Portcullis House

(6) People born with a congenital insensitivity to pain succumb to a series of injuries without noticing the damage being caused. One lady with this condition placed the family casserole into the centre of the dining table using her bare hands; the table promptly erupted in flames. Patients often die because of the injuries sustained. See Melzack and Wall, The Challenge of Pain, Penguin 1988

(7) Anand KJ, Craig KD. New perspectives on the definition of pain, Pain 1996 Sep;67(1):3-6

(8) Hobson P. The cradle of thought: Exploring the origins of thinking. Pan Macmillan 2004; Dennet D. Kinds of minds: The origins of consciousness. Phoenix 1997

(9) Malik K. Man, beast and zombie: What science can and cannot tell us about human nature. Weidenfeld & Nicolson, 2000

(10) Anand KJ, Sippell WG, Schofield NM, Aynsley-Green A. Does halothane anaesthesia decrease the metabolic and endocrine stress responses of newborn infants undergoing operation? BMJ 1988 Mar 5;296:668-672

(11) Unborn child pain awareness act, 2005

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