Fetal pain

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Fetal pain

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Fetal pain

  1. 1. ARTICLE IN PRESS Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9 Contents lists available at ScienceDirect Best Practice & Research Clinical Obstetrics and Gynaecology journal homepage: www.elsevier.com/locate/bpobgyn8Foetal pain?Stuart W.G. Derbyshire, PhD, Senior Lecturer *University of Birmingham, School of Psychology, Edgbaston B15 2TT, UKKeywords: The majority of commentary on foetal pain has looked at thePain maturation of neural pathways to decide a lower age limit fornociception foetal pain. This approach is sensible because there must beabortion a minimal necessary neural development that makes pain possible.surgery Very broadly, it is generally agreed that the minimal necessaryhuman neural pathways for pain are in place by 24 weeks gestation.development Arguments remain, however, as to the possibility of foetal painconsciousness before or after 24 weeks. Some argue that the foetus can feel painawareness earlier than 24 weeks because pain can be supported by subcor-foetal tical structures. Others argue that the foetus cannot feel pain at any stage because it is maintained in a state of sedation in the womb and lacks further neural and conceptual development necessary for pain. Much of this argument rests on the definition of terms such as ‘wakefulness’ and ‘pain’. If a behavioural and neural reaction to a noxious stimulus is considered sufficient for pain, then pain is possible from 24 weeks and probably much earlier. If a conceptual subjectivity is considered necessary for pain, however, then pain is not possible at any gestational age. Regardless of how pain is defined, it is clear that pain for conceptual beings is qualitatively different than pain for non- conceptual beings. It is therefore a mistake to draw an equiva- lence between foetal pain and pain in the older infant or adult. Ó 2010 Elsevier Ltd. All rights reserved. During the past 10 years there has been increasing legislative interest in the possibility of foetalpain. In 2006, the US House of Representatives debated the Unborn Child Pain Awareness Act.1 The billsecured a majority but failed to obtain the two-thirds majority necessary to pass it as a law. Efforts atthe state level have been more successful. At least 25 US states have deliberated on foetal pain * Tel.: þ44 0121 414 4659; fax: þ44 0121 414 4897. E-mail address: s.w.derbyshire@bham.ac.uk1521-6934/$ – see front matter Ó 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.bpobgyn.2010.02.013 Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice & Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  2. 2. ARTICLE IN PRESS2 S.W.G. Derbyshire / Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9legislation and at least eight (Alaska, Arkansas, Georgia, Oklahoma, South Dakota, South Louisiana,Texas and Wisconsin) now have legislation requiring that women seeking abortions be informed of thepossibility of foetal pain. Foetal pain has also been widely debated in Britain. The British Medical Research Council (MRC) andthe Royal College of Obstetricians (RCOG) have both issued reports on this subject2,3; the issue of foetalpain was debated upon by the British Parliamentary Science and Technology Select Committee in2008.4 To the author’s knowledge, however, no British or European legislation makes any directreference to foetal pain. Increasingly invasive surgical and other medical procedures performed in utero have also generatedcontemporary interest in foetal pain. Although rare, it is now possible to perform foetal surgery forconditions such as lower urinary tract obstruction, hydrothorax, cystic adenomatous malformation ofthe lung, congenital diaphragmatic hernia, spina bifida and large sacrococcygeal teratomas.5 Morecommonly, but still relatively rare, the foetus may be exposed to invasive interventions for thetransfusion of donor red cells into the foetal intrahepatic umbilical vein or the peritoneal cavity. Inaddition, drainage of abnormal fluid collections, for example, a dilated bladder or hydrothorax, can beachieved by a single aspiration using a needle or the percutaneous insertion of an indwelling shunt intothe amniotic cavity. Similarly, endoscopic placement of a balloon that is inflated in the foetal tracheacan be used to improve outcome in cases of congenital diaphragmatic hernia. Finally, surgical abortioncan obviously expose the foetus to intensely invasive procedures. Resolving the question as to whether the foetus feels pain is not straightforward, most attempts atanswering the question consider the neural pathways that are necessary for pain and ask when thosepathways are present and functional in the foetus.6–10 This approach is useful because it is reasonableto assume that there is a necessary neural biology that renders pain experience possible. If the foetuslacks that necessary neural biology then it is reasonable to assume that it cannot feel pain. Theapproach is limited, however, by knowledge of the necessary neural biology. Although there isa general consensus that certain cortical structures are necessary for pain, legitimate arguments thatcortical structures are not necessary continue to be raised.9,11,12 This article will first consider the neuralpathways that might be necessary for pain and then go on to consider the limitations of deciding foetalpain based on the existence of such pathways.The neuroanatomy of pain A considerable amount is known about the biological structures involved in painful experience.Humans, and many other species, have neural structures that respond preferentially to noxiousstimuli.13–15 Beginning in the periphery, there are nerve endings that preferentially transmit noxiousinformation. They are the free nerve endings that arise mostly from the peripheral termination ofA-delta and C fibres. The free nerve endings are polymodal and can respond to non-noxious andnoxious temperatures or mechanical stimuli. When activity in A-delta and C fibres gives rise to pain orbehaviour associated with pain then they are labelled as nociceptors. Fibres that only respond in thenoxious range are labelled as nociceptive specific, while those that respond across the noxious andnon-noxious range are labelled as wide dynamic range. The primary afferent A-delta and C fibres terminate on neurons in the superficial dorsal horn of thespinal cord. Ascending projections to the thalamus originate from the most superficial layer, known aslamina I, and project contralaterally in the spinothalamic tract (STT). Intracellular recordings fromlamina I neurons revealed neurons with seemingly modality-specific responses. One class of neuronswere nociceptive specific, responsive only to noxious pinch, heat or both. Another class werethermoreceptive-specific, responding only to non-noxious cooling. A final class were polymodal,responding to heat, pinch and cooling. Provocatively, the existence of lamina I neurons, with specificresponses and distinct morphology, motivated the suggestion that there are dedicated pathways forpain and temperature detection.14 A series of neuroimaging studies have demonstrated consistent activation of several cerebralstructures during pain.16 These structures include the primary and secondary somatosensory corticesand anterior cingulate, prefrontal and insular cortices. In combination, these structures are thought tocoordinate defensive reactions and generate the sensory and unpleasant feelings associated with pain. Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice & Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  3. 3. ARTICLE IN PRESS S.W.G. Derbyshire / Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9 3Thus, a noxious stimulus sets in motion a train of biological events that acts to prevent further injury.People who lack nociceptors or have other biological deficits associated with the nociceptive system donot engage in defensive behaviours and do not report experiences of pain.13 Consequently, they sufferconsiderable, often life-threatening, injuries. The first evidence for an intact nociceptive system in the foetus emerges at about 8 weeks gesta-tional age (GA). At this stage, touching the perioral region will result in movement away, indicating thepresence of sensory receptors and, at least, spinal or brainstem-mediated reflex action.17 Some claimthat by 8 weeks GA, there are connections from the periphery and through the spinal cord to thethalamus (http://www.abortionfacts.com/online_books/love_them_both/why_cant_we_love_them_both_14.asp) but these claims are yet to receive any peer-reviewed verification. At 8 weeks GA, the foetal brain is profoundly immature. There is no indication of maturationsuch as cortical sulcation and gyration18 or the appearance of a laminar structure in either thethalamus or the cortex.19,20 The external wall of the brain is about 1 mm thick, consisting of aninner and outer layer, but without a cortical plate from which the cortical layers will later develop.21The cell density of the outer layer is significantly higher than that of a newborn or adult butcontains large neurons that resemble those described in the older foetus. Beginning from about 9weeks GA, there is thalamic fibre penetration directly into this outer layer that stimulates deve-lopment and maturation of these large neurons.20 There is speculation that by 11 weeks GA theseprojections may be functional. The possibility of functional neurons from the periphery, into thethalamus and into the outer layer of the developing cortex places a lower time limit for foetal painat around 11 weeks GA. Between 12 and 18 weeks, the formation of the subplate begins and the first projections fromthe thalamus into the subplate appear.21–23 The subplate is a transient brain structure formeddirectly underneath the developing cortical plate. Neurons arrive in the subplate and are held forseveral weeks until the cortical plate becomes growth-permissive and facilitates neuronal invasionof the cortical plate.24 The relocation of neurons from the subplate to the cortical plate beginsaround 24 weeks GA and is extremely rapid from about 34 weeks. Afterwards the extracelluarmatrix and other growth-related and guidance molecules disappear leading to the dissolution ofthe subplate.21 Morphological features of maturity can be gradually observed from about 12 weeks GA. At 13weeks, for example, a linear furrow or groove can be observed at the limit of the temporal lobe belowand the insula, frontal and parietal lobes above.18 Around 15 weeks GA, this groove becomes part of theinsular cortex, which is believed to be the first lateral cortical region to develop and is a key regioninvolved in the experience of pain.16 The subplate has also been observed to thin in areas where corticalfolding occurs, such as the parieto-occipital sulcus, and in the insula and cingulate gyrus at least from20 weeks GA.25 It is currently uncertain whether this thinning is due to earlier maturation of theseregions, and potentially earlier synaptic activity in the insula and cingulate cortex, which are both keyareas in the experience of pain16, or due to incidental morphological changes. Nevertheless, before 26weeks GA, the foetal brain is largely smooth with only minor evidence of sulcation and gyration.Massive growth of the brain after 34 weeks rapidly results in the characteristic folds and surfacefeatures of the more mature brain. By 24 weeks GA, substantial thalamocortical afferents have accumulated at the superficial edge ofthe subplate, which is the stepping-off point for axons growing towards their final cortical targets.21Between 24 and 32 weeks there is substantial ingrowth of thalamocortical axons in the corticalplate of the frontal, somatosensory, visual and auditory cortex and formation of the first synapses in thedeep cortical plate. Clear evidence of synaptic activity following auditory stimulation has beenrecorded from around 26 weeks in utero and somatosensory responses have been recorded inpremature neonates of 25 weeks GA following a noxious heel lance.26,27 By around 24 weeks GA, therefore, it can be assumed that noxious peripheral events causea response in the primary sensory cortex indicating the presence of a spinothalamic connection. Longaxonal tracts now course from the periphery and through the brain to the cortex. It is generallyaccepted that the necessary neural structures for pain are in place and are functional by 24 weeksGA.6–10 Thus, it is possible that measures to prevent pain might be appropriate during invasiveprocedures after 24 weeks GA. Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice & Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  4. 4. ARTICLE IN PRESS4 S.W.G. Derbyshire / Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9Further developments Recently, however, it has become clear that the pre- and post-birth environments are very differentwith potentially important consequences for painful experiences. It is also becoming clear thatcompletion of the major pathways from the periphery to the cortex, at around 24 weeks GA, does notsignal the end of cortical development but rather the beginning of a further maturational process. In an extensive and important review, Mellor et al. 28 described evidence suggesting that the foetusnever enters a state of wakefulness in utero. This conclusion was based largely on observations of foetallambs. Rigatto et al. 29, for example, directly observed an unanaesthetised sheep foetus, in utero, througha Plexiglas window, for a total of 5000 h without observing signs of wakefulness such as eyes opening orcoordinated movement of the head. Mellor and colleagues suggest several factors explain this lack ofwakefulness including the environment of the womb, which is warm, buoyant and cushioned, and thepresence of a chemical environment that preserves a continuous sleep-like unconsciousness orsedation. The environment of the womb and the chemical suppression of wakefulness maintainunconsciousness and suppress higher cortical activation in the presence of intrusive external stimu-lation. The foetal response to hypoxia and asphyxia, for example, is characterised by apnoea, cessation offoetal body movements and a shift to a more quiescent Electroencephalographic (EEG) state indicativeof unconsciousness.30,31 A series of studies have also demonstrated that as spinothalamic pathways complete theirconnections with the cortex, from around 24 weeks GA, they increasingly stimulate intracorticalpathways into development, which is the next major phase of neuronal maturation. This phaseinvolves elaboration of dendrites and axons, formation and regression of synaptic connections andselective elimination of cell populations and corresponds to the cortical maturation described byGoldman-Rakic32 in primates and by Chugani33 in humans. McKinstry et al. 34 illustrated the effects ofthis development using diffusion tensor imaging (DTI) in neonates born at 26 and 35 weeks GA.Neonates born at 26 weeks GA have a cortical cell structure dominated by radially orientated dendritesthat inhibit the spread of water parallel to the surface of the brain. Consequently, DTI measures anelongated diffusion of water in the cortex. Neonates born at 35 weeks GA, in contrast, have a corticalcell structure with radially orientated and basal dendrites that inhibit the spread of water in alldirections. Consequently, DTI measures a spherical diffusion of water in the cortex. This proliferation ofcortical neurons and the overproduction of their arborisation and synaptic contacts begins prenatally,as illustrated by McKinstry et al.34, but continues postnatally, along with synaptic elimination, pruningand programmed cell death.32,33,35,36 The sedation of the foetus in utero, and the further development of the cortex, which only completesafter birth, imply that it is only after birth, when the infant awakens and cortical developmentcompletes, that pain will be experienced. To put that slightly differently, it is seemingly reasonable,given the immature nature of the foetus and the apparent lack of wakeful activity, to reject thepossibility of foetal pain on the grounds of pain being objectively impossible in utero.The meaning of biological immaturity The conclusion that the foetus cannot experience pain at any stage of development has met withconsiderable resistance.9,11 Opponents point out that the cortex might not be the only neural structurecapable of processing pain. Subcortical structures, such as the brainstem, for example, respond tonoxious stimulation. Subcortical responses occur in response to needling from 18 weeks GA.36 Inaddition, anencephalic infants, who typically lack almost the entire cortex, demonstrate a capacity tolearn and show evidence of emotion12,37, which supports the possibility of some kind of brainstem-mediated pain experience.11 An anencephalic foetus also withdraws from noxious stimulation,demonstrating that withdrawal is mediated at a subcortical level.38 Infants with significant neonatalneurological injury due to a parenchymal brain injury also respond to noxious stimulation witha pattern of biobehavioural and facial reactions similar to infants without brain injury.39 If the foetus is sedated and asleep in the womb then it might be possible to dispense with allarguments based on neurobiology because it is typically assumed that a sleeping organism cannot feel.Mellor et al. 28 propose that the foetus is unconscious based on the presence of powerful sedating Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice & Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  5. 5. ARTICLE IN PRESS S.W.G. Derbyshire / Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9 5chemicals in the womb (most notably adenosine), the presence of sleep-like EEG patterns observed inthe lamb foetus that enter a more quiescent state during stress, and a lack of movement during stress.Unfortunately, these conditions do not guarantee or dictate a lack of wakefulness. Relaxation and sleepcan be broken by noxious stimuli40 and although the EEG activity in the lamb foetus enters a state ofrelative quiescence during stress (such as caused by umbilical cord occlusion) there are clear indica-tions of large spikes within that quiescence.31 Rather than EEG silence during stress, there is a shiftfrom one EEG pattern to another and we have no direct means of assessing what either pattern meansin terms of experience. It is also questionable whether the stress of umbilical cord occlusion iscomparable to the nociceptive stress that will occur during surgery. A series of studies with rats have also demonstrated that mammalian foetal behaviour is complexand organised. Foetal behaviour includes temporal rhythmicity, movement synchrony and motorcoordination that are related to postnatal grooming, suckling and locomotor behaviour.41–44 The ratfoetus responds vigorously to chemical stimulation, such as a lemon infusion, and preconditioningwith other chemical stimulation, such as mint, modifies these responses.45 Human foetuses also detectand respond to chemical stimuli46, move away when approached with a scalpel or needle duringsurgical procedures47 and show evidence of learning in utero.48,49 While these responses might occurduring a state of sleep or sedation they are certainly not incompatible with wakefulness. Associating EEG patterns during gestation with sleep-like states is also difficult because there is, ingeneral, no clear cut-off between conscious and unconscious EEG activity.50,51 For the neonate, andpresumably the foetus, sleep is accompanied by ongoing background EEG without obvious differencesbetween wake and sleep.52,53 These observations of cortical activity during ‘sleep’ in the neonate raisethe question of what ‘sleep’ and ‘wakefulness’ actually mean for the neonate or foetus. A subcortical response to noxious stimulation and lack of uncertainty regarding the nature of foetalconsciousness makes a definitive rejection of foetal pain difficult. The difficulty stems not just from a lackof neuroscientific knowledge but also from a lack of substance with regard to the nature of sensoryexperience. Without a satisfactory or comprehensive approach to the nature of sensory experience,terms such as ‘awake’ or ‘conscious’ or ‘pain’ and so forth take on a somewhat arbitrary character and canbe attached to any apparently coherent neural behaviour. Certain patterns of EEG activity might or mightnot be associated with being awake; certain neuronal activity might or might not be associated withbeing conscious; and certain areas of the brain might or might not be necessary for pain. There is nomeans of deciding these issues without an adequate account of the subjective terms in use.Why the definition of pain is critical How we define pain is critical. Defining pain as the response to noxious stimulation might seemsensible until it is realised that such a definition will allow almost anything to be in pain because evenrocks respond to violent force by shattering and thermostats respond to high temperatures bychanging their internal state. Allowing rocks and thermostats to have a pain response is much toopermissive. Furthermore, a definition of pain based on response leads to a tautological understandingof pain. Pain is defined in terms of a stimulus that is deemed to be painful because it elicits the painresponse. Put simply: pain is defined as pain.54,55 A definition of pain that includes the content of pain is required to avoid tautology. Definitions ofpain that avoid tautology usually include cognition, sensation and affective processes such as thatprovided by the International Association for the Study of Pain (IASP).56 The IASP have defined pain as‘‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, ordescribed in terms of such damage. pain is always subjective. Each individual learns the application ofthe word through experiences related to injury in early life.’’ By this definition, pain is no longer regarded as merely a physical sensation of noxious stimulus anddisease but is seen as a conscious experience which may be modulated by mental, emotional andsensory mechanisms and includes both sensory and emotional components. The multidimensionalemphasis and reference to subjectivity makes it difficult to deny an active cortical role for painexperience. Suppression of cortical activity is widely associated with profound loss of consciousexperience.57 For pain to be supported by subcortical structures, therefore, requires that pain beredefined as something less than a multidimensional, subjective experience. Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice & Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  6. 6. ARTICLE IN PRESS6 S.W.G. Derbyshire / Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9 Those that support the possibility of foetal pain have made attempts to change the IASP definition ofpain.58 Those efforts have largely focussed on removing the apparent requirement for language fromthe definition and resulted in a new note being added to the IASP definition: ‘‘The inability tocommunicate verbally does not negate the possibility that an individual is experiencing pain and is inneed of appropriate pain-relieving treatment.’’ The note clarifies that being unable to talk does not mean a person is unable to experience pain butit does not change the substance of the IASP definition. It is unlikely that the efforts to change the IASPdefinition were intended to clarify something as obvious as silence not delivering pain relief.Presumably, the intention was to reduce the requirements for pain experience so that pain could bemore easily attributed to inherently, rather than temporarily, non-verbal beings such as the foetus.Rather than something multidimensional and subjective, pain is reduced to a physical, raw nature bystripping away the layers of conceptualisation that we associate with language. The challenge is tounderstand pain as something apprehended rather than comprehended. Pain is something that just is,an experience that is complete but irreducible and immediate: a pure immediacy that cannot beallowed any durability. Conceptual, language-ridden beings such as persons cannot experience sensation as a pureimmediacy. Sensory experiences in conceptual beings are propositional. Such beings are not merely inpain but know that they are in pain. Knowing that I am in pain involves concepts – ‘sore’, ‘stabbing’,‘damage’, ‘threat’ and ‘body’ – that are themselves rooted in general beliefs. For conceptual beings,there is no such thing as a pure pain experience that can be extracted from those general beliefs. Everypainful experience will invoke its own set of autobiographical associations and expectations that formboth the content and the context of the pain experience. Conceptual beings cannot return to a more innocent, aconceptual state. Perception in conceptualbeings is structured by concepts and categories from language and thought and is directed towardswhat is recognised as threatening or desirable. The perceptual field no longer dictates behaviour orexperience because conceptual beings highlight the structurally relevant elements, keeping the correctcomponents together and the incorrect components apart. Perception demands a flow of interpreta-tion that informs and constitutes the experience. Every experience that a conceptual being has willfollow and be dependent upon a period of conceptual development. The foetus has no options regarding its behaviour in the presence of noxious stimuli. It cannot, forexample, decide it is in his/her best interests to remain still during surgery any more than he/she canlaunch a protest against an abortion. The foetus must react according to the dictates of its biology in thepresence of an eliciting stimulus. Anything further will require a conceptual apparatus that will beprovided as language and higher forms of thought and behavioural organisation become possiblethrough development. The suggestion that the foetus can feel an equivalent pain to that of an older,conceptual infant misses or denies the necessary role of development in constructing sensorialexperience. Nevertheless, the question remains, what is sensation before conceptual development?Sensation before conceptual development Insisting that only conceptual beings have the apparatus to engage in sensation means denyingsensation to all animals and all infants less than approximately 2–3 months of age. Such a positionstrikes many as implausible.9,12,58,59 As discussed earlier in this article, one possible way to avoid theconclusion that only human beings of a certain advanced age experience sensation is to definesensation as something raw and pure. Animals and the foetus might have a perceptual sensitivity tofeatures of the environment that are entirely contained within nature. What exists in animals and thefoetus also exists in conceptual beings but perceptual sensitivity in conceptual beings is taken up intothe ambit of consciousness where raw immediacy becomes abstract experience.59 Even in non-verbal, aconceptual, creatures, however, there is more to perceptual sensitivity thanmerely neural activity.60,61 The visual system endows objects, for example, with colour in the samesense that cows endow grass with the character of food. Grass is food for cows because cows eat grass.If cows did not eat grass then grass would not be food. The existence of grass as a food for cows dependsupon the relationship between cows and grass and that relationship cannot be reduced to a neuralevent because the neural event is only one part of the story. Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice & Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  7. 7. ARTICLE IN PRESS S.W.G. Derbyshire / Best Practice & Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9 7 Sensory perception might be viewed in the same way. Sensations are not projected into objects,which cannot sense, but sensations arise through a relation with the object. That relationship makesthe appearance and existence of the object, as qualities of the object, possible. Colours, for example,inhere in objects only by virtue of their relations with a being perceptually sensitive to colour. In similarfashion, noxious stimuli are painful only by virtue of their contact with a being perceptually sensitive tostimuli in the noxious range. The entire experience is more than just nervous tissue activity eventhough the physiological or sensory structure of the perceptually sensitive being determines theexperienced content of the stimulus. This observation is important because it allows us to potentiallysay that the foetus feels pain without forcing us to also say that rocks and thermostats feel pain. For the foetus, an existence of ‘pain’ rests upon the existence of a stimulus that poses a threat totissue, being detected by a nervous system capable of preferentially responding to stimuli that posea threat to tissue. The entire experience is completely bounded by the limits of the sensory system andthe relationship between that system and the stimulus. If pain is conceived of in this manner then itbecomes possible to talk of foetal pain anytime between 10 and 17 weeks GA when nociceptorsdevelop and mature, and there is evidence of behavioural responses to touch.35 Further developmentsof the nervous system then provide for alterations or elaborations of the pain response; eachdevelopment potentially provides what some have called an experience of pain relevant to that stageof development.9,58Conclusions Decisions regarding foetal pain are typically resolved by reference to neuroanatomy. Before thepresence of a system capable of detecting noxious events, it is reasonable to deny the possibility of painin utero. Deciding the minimally necessary neuroanatomy, however, is not straightforward. There isconsiderable disagreement regarding the contribution of the cortex and the possibility of pain, andother conscious experiences, being supported subcortically. One reason for this disagreement is thelack of precision in defining what is meant by ‘pain’. If pain is defined in terms of a noxious stimulusbeing detected by a nervous system that can preferentially respond to stimuli in the noxious range thenpain can be attributed to the foetus from around 10 weeks GA. However, if pain is defined as anelaborate multidimensional experience that is subjective, then pain can never be attributed to thefoetus because it is implausible to attribute that much conceptual activity to the foetus.61 This review is agnostic with regard to which view of pain is ‘correct’. It is possible that both views arecorrect or both views are incorrect but it is not possible that both views are equivalent. Pain ina conceptual being is both apprehended and comprehended whereas pain in a non-conceptual being is,at most, only apprehended. Once pain is comprehended, there is no return to a more innocent state ofapprehension. Sensory experience for conceptual beings is not the product of raw experiences stackedtogether but is a profoundly different way of experiencing the world. Pain for the foetus, whatever thatmight feel like, will be bounded by the activity in dedicated neural pathways set in motion by a stimulusin the noxious range. The foetus just is, and his experiences just are, and they just are without furtherregard. Pain for the conceptual infant, in contrast, will open out into the unfolding of his or her life to beconnected with a vast array of other sensations, emotions and understanding of the world and the self.The conceptual being has a self-existence that has great regard towards all experience. Practice points There are numerous surgical procedures, in addition to surgical abortion, that may induce foetal pain but that remains uncertain. The uncertainty regarding foetal pain means that any direction to change clinical practice based on foetal pain would be premature. The use of analgesia or anaesthetic during in utero procedures should remain at the discretion of the medical team responsible for the procedures. Please cite this article in press as: Derbyshire SW, Foetal pain?, Best Practice Research Clinical Obstetrics and Gynaecology (2010), doi:10.1016/j.bpobgyn.2010.02.013
  8. 8. ARTICLE IN PRESS8 S.W.G. Derbyshire / Best Practice Research Clinical Obstetrics and Gynaecology xxx (2010) 1–9 Research agenda Clinical trials evaluating the clinical benefit of analgesia or anaesthesia during in utero procedures. Neural development in utero. Psychological investigations of sentient versus propositional sensory experience.References 1. The Unborn Child Pain Awareness Act of 2005. S. 51. Available online: http://frwebgate.access.gpo.gov/cgi-bin/getdoc. cgi?dbname¼109_cong_billsdocid¼f:s51is.txt.pdf. 2. Medical Research Council (government body), United Kingdom. August 28, 2001. Report of the MRC Expert Group on Fetal Pain. www.mrc.ac.uk/pm/pdf-fetal.pdf. 3. Fetal awareness report of a working party. London: RCOG Press, 1997. 4. House of Commons Science and Technology Committee: scientific developments relating to the Abortion Act 1967 October 2007, http://www.publications.parliament.uk/pa/cm200607/cmselect/cmsctech/1045/1045i.pdf. 5. James D. Fetal medicine. 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