Fetal pain do we know enough to do the right thing

1. A 2008 Reproductive Health Matters.
All rights reserved.
Reproductive Health Matters 2008;16(31 Supplement):117–126
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Fetal Pain: Do We Know Enough to Do the Right Thing?
Stuart WG Derbyshire
Senior Lecturer, University of Birmingham, School of Psychology, Edgbaston, UK.
E-mail: s.w.derbyshire@bham.ac.uk
Abstract: Raising the possibility of fetal pain continues as a tactic to undermine support for
abortion in the US and the UK. This paper examines anatomical and psychological developments in
the fetus to assess the possibility of fetal pain. Neurobiological features that develop at 7, 18 and
26 weeks gestation suggest an experience of pain in utero. Pain, however, cannot be inferred from
these features because they are not informative about the state of consciousness of the fetus and
cannot account for the content of any presumed pain experience. We may be confident the fetus
does not experience pain because unique in utero neuroinhibitors and a lack of psychological
development maintain unconsciousness and prevent conscious pain experience. Before an infant can
experience sensations and emotions, the elements of experience must have their own independent
existence in the infant’s mind. This is achieved after birth through discoveries made in action and in
patterns of adjustment and interaction with a caregiver. Recommendations about anaesthetic
practice with the fetus and the newborn or young infant should not focus on pain but on outcomes
with obvious, and measurable, importance. In the case of an unwanted pregnancy, the health of the
woman should guide anaesthetic practice. In the case of a wanted pregnancy, the survival and
long-term health of both the woman and fetus should guide anaesthetic practice. In any case,
current evidence does not support efforts to inform women of the potential for fetal pain. Any
policy to mitigate fetal pain could expose women to inappropriate intervention, risk and distress.
A2008 Reproductive Health Matters. All rights reserved.
Keywords: pain, nociception, development, infant, fetal, neuroanatomy, abortion law and policy
nitrous oxide and curare.4 This finding, and
T
HE possibility of fetal pain continues to be
raised as a tactic to undermine support for later reports,5,6 led to a major reconsideration of
abortion in the US and the UK. In the US, analgesic practice on neonates. In 1992, the New
federal legislation requiring discussion of fetal England Journal of Medicine ran an editorial
pain before an abortion has been proposed and calling on clinicians to ‘‘Do the Right Thing’’
recently defeated.1 In the UK, images of the fetus concluding that ‘‘it is our responsibility to treat
produced by 4-D ultrasonography have fuelled a pain in neonates and infants as effectively as we
reassessment of fetal capabilities and sugges- do in other patients’’.7 Since then it has become
tions that the fetus can respond emotionally and usual to assume that neonates feel pain and this
cognitively, with the implication that the current assumption has led inevitably to speculation
UK abortion law should require procedures miti- that the fetus may also experience pain.8 Con-
gating against fetal pain.2,3 sequently there are calls for also reconsidering
This debate raises several important questions analgesic practice on fetuses and to provide
about the nature of fetal pain and proper forms pain relief for the fetus before an abortion. The
of treatment. It has been known for some time assumption of fetal pain, however, should not
that neonates receiving fentanyl anaesthesia in go unchallenged: the available evidence regard-
preparation for surgery have improved clinical ing neuronal development and pain perception
outcomes compared with neonates receiving raise questions about whether fetal pain is
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possible and the appropriateness of legislation to ring out pain is developed. For this review, a
to prevent fetal pain. noxious stimulus includes any sensory insult that
To address whether fetal pain relief is appro- might normally cause pain in a conscious adult.
priate, I propose to divide the question of fetal Free nerve endings, the ‘‘alarm buttons’’, begin
pain into its two component parts: the first to develop from about seven weeks gestation and
addresses the developing neurobiology of the projections from the spinal cord, the major
fetus and the second the developmental psy- ‘‘cable’’ to the brain, can reach the thalamus (the
chology of pain. With regards to neurobiology, lower ‘‘alarm’’) from seven weeks gestation.10–12
there are a series of important points in fetal An intact spinothalamic projection might rea-
development that may be relevant to pain sonably be viewed as the minimal necessary
processing. Although fetal development is con- anatomical architecture to support pain process-
tinuous, new features have been observed at 7, ing. These facts place a lower limit for fetal pain
18 and 26 weeks gestation and used to suggest at seven weeks gestation.
an experience of pain in utero. These new At seven weeks gestation, however, the nervous
features are tremendously interesting and excit- system is highly immature. There is no indication of
ing, but they do not tell us the fetus is expe- a laminar structure, a defining feature of maturity,
riencing pain. It is here that my critique diverges in either the thalamus or the cortex.13,14 The exter-
from some of the current discussion about fetal nal wall of the brain is about 1mm thick and con-
pain and sentience.7–9 In my view, it is a mistake sists of an inner and outer layer with no cortical
to infer subjective experience, including pain, plate from which cortical layers will later develop.
from measures of anatomy, stress hormones and The cell density of the outer layer is much higher
fetal movements, because this approach fails to than that of a newborn or adult but contains large
account for the contents of experience in gen- neurons that resemble those described in the older
eral, and of pain in particular. fetus. Thalamic fiber penetration stimulates deve-
Although we normally think of pain as some- lopment and maturation of these large neurons
thing automatic and private, and therefore natural, beginning from about 12 weeks gestation. Without
such a view is mistaken. Firstly, pain is dependent thalamic projections these neurons cannot be pro-
on general cognitive processes that characterise cessing noxious information from the periphery.
our mental lives because pain itself contains sen- The first projections from the thalamus towards
sory and affective components, which we attend the cortex (the higher ‘‘alarm’’) are apparent from
to and process. Secondly, when we are in pain we 12-16 weeks gestation. By this stage, the outer
remain self-located within that experience: you layer of the brain has undergone a secondary split
know that it is you that hurts. Pain is therefore to provide for development of the outer cortical
dependent on psychological developments that rim with the subplate developing below. The
support cognition, and self-awareness and these subplate contains several neuronal types and is
psychological developments need time to appear. a wide zone developing below the cortical plate in
Fetal pain is not possible because of the lack of the human fetal brain. The thalamic projections
development necessary to support the experience. that develop from 12–16 weeks are into the sub-
plate. Spinothalamic projections into the sub-
plate have been described as providing a minimal
The neurobiology of the fetus: necessary anatomy for pain experience,9 but
anatomical pathways this view has to account for the transient nature
It is heuristically useful to view the pain system as of the subplate and its apparent role in the mat-
an alarm system. In this view, a noxious stimulus uration of functional cortical connections. The
is an event that activates free nerve endings in subplate is generally regarded as a ‘‘waiting com-
the skin similar to pushing an alarm button. The partment’’ where neurons wait before migrating
electric cable from the button to the alarm is simi- and forming mature cortical connections in the
lar to the connection between the nerve endings cortical plate above.15–17 This maturational pro-
and the brain. Finally, the brain is similar to the cess gradually causes dissolution of the subplate.
alarm ringing out pain. Whether the fetus is While it has been suggested that the subplate
responding to a noxious stimulus with pain can may be a substrate for functional and behav-
then be decided in part by asking when the alarm ioural phenomenon that occur in the womb,15
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noxious processing and pain experience clearly injury or psychologic trauma and does not include
extend beyond this timeframe. The dissolution any conscious components that may accompany
of the subplate is difficult to explain if the sub- the stress response.24 Anand’s seminal work with
plate provides a mature function. Possibly, the neonates undergoing surgery demonstrated that
maturational role of the subplate involves plac- fentanyl added to the anaesthetic regimen sig-
ing neuronal connections that are already fully nificantly reduces the stress response to invasive
functional. This speculation, however, is incon- practice.4 Specifically, plasma adrenalin, nor-
sistent with what is known about cortical deve- adrenaline, glucagon, aldosterone, corticoster-
lopment.15–17 A lack of functional neuronal one, 11-deoxycorticosterone and 11-deoxycortisol
activity within the subplate undermines the claim levels were significantly increased in the non-
to fetal pain experience before spinothalamic fentanyl group up to 24 hours after surgery.
projections arrive in the cortical plate. Reducing the normal stress response was consid-
Most current theories of pain consider an ered to be responsible for the improved clinical
intact cortical system to be necessary for pain outcome of the fentanyl group who required less
experience.18–20 In support are functional imag- post-surgical ventilator support and had reduced
ing studies demonstrating activation within a circulatory and metabolic complications.
network of cortical regions to correlate with More recently, the stress response to invasive
reported pain experience.20,21 Furthermore, cor- practice has been examined in the fetus to dem-
tical activation can create the experience of pain onstrate increased cortisol and h-endorphin cir-
even without actual noxious stimulation.20,22 culation following intrauterine needling of the
These observations suggest thalamic projections fetus beyond 18 weeks gestation.25 Further
into the cortical plate as a minimal necessary studies have demonstrated that the fetal stress
anatomy for pain experience. Currently it is response includes haemodynamic changes in
believed that these projections begin to form blood flow to protect essential organs, such as
from 23 weeks gestation, which means the lower the brain, and blunting the stress response when
limit of fetal pain experience might be 23 weeks. providing opioid analgesia to the fetus.26,27
It remains possible, however, that thalamic pro- The changes in cortisol and h-endorphin
jections into the cortical plate are developing have been interpreted as due to direct fetal
before 23 weeks and that earlier projections might hypothalamic-pituitary-adrenal axis (HPA) acti-
carry signals indicating injury or potential tissue vation. The presence of an intact HPA axis at
damage, known technically as nociception. 18 weeks gestation is a suitable conclusion, but
23–25 weeks gestation is also the time at which the HPA axis is a subcortical system and so its
the peripheral free nerve endings and their pro- activity is not evidence for cortical awareness
jection sites within the spinal cord reach full or conscious pain perception. Stress hormones
maturity,10 and when noxious stimulation clearly increase during surgical procedures carried out
evokes haemodynamic changes in the somato- under general anaesthesia,28,29 and in brain-dead
sensory cortex.23 By 26 weeks gestation the char- patients during organ harvesting,30,31 despite
acteristic layers of the thalamus and cortex are suppression of cortical activation.32
becoming visible with obvious similarities to the Behavioural responses have also been used as
future adult brain.16,17 indicators of a stress response.7,33,34 Responses
The subplate reaches its developmental peak to touch begin at 7–8 weeks gestation when
at 28 weeks gestation and is followed by mas- touching the peri-oral region results in a contra-
sive transfer of subplate fibers into the cortical lateral bending of the head. The palms of the
plate. After that point, the cortical plate under- hands become sensitive to stroking at 10-11 weeks
goes tremendous growth – increasing in volume gestation and the rest of the body becomes
by 50% between 29 weeks gestation and term.15 sensitive around 13-14 weeks gestation.35 These
are spinal reflex responses, not dependent
on brain activity, and thus not indicators of
The neurobiology of the fetus: the pain experience.
hormonal ‘‘stress response’’ Shortly after developing sensitivity, repeated
A stress response is characterised by the hor- skin stimulation results in hyperexcitability
monal and metabolic changes that follow physical and a generalised movement of all limbs. After
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26 weeks, this generalised movement gradually A potential function of the thalamic reticular
gives way to more coordinated behavioural nucleus could be to suppress fetal arousal
responses that signal improved organisation through inhibition of thalamocortical activa-
within the nervous system. Infants delivered at tion.15 Inside the womb, alertness and motion
26–31 weeks, for example, show coordinated can only cause the expenditure of energy with
facial expressions in response to heel prick that little possibility of escape or other advantage.
are not present in younger infants.33 Although Outside the womb, limits on behaviour become
these later behavioural responses are not spinal detrimental to survival.
cord reflexes, the responses are still unlikely to Further obstacles to equating the fetal mind
involve higher cortical centres. An anencephalic with that of an adult or older child are the many
fetus withdraws from noxious stimulation, dem- environmental factors inherent to the womb
onstrating behavioural mediation at a subcor- that distinguish the fetal and neonatal environ-
tical level.36 Similarly, infants with significant ment, and have been the subject of review else-
neonatal neurological injury because of a paren- where.38 The environment of the womb consists
chymal brain injury respond to noxious stimula- of warmth, buoyancy and a fluid-cushioning
tion with a pattern of biobehavioural reactions of tactile stimulation. The fetus and placenta
similar to infants without brain injury.37 provide a chemical environment to preserve
continuous sleep-like unconsciousness and to
suppress higher cortical activation in the pres-
Exploring fetal ‘‘psychology’’ ence of intrusive external stimulation. The fetal
Without verbal report or other direct access to response to hypoxia and asphyxia, for example,
the fetal ‘‘mind’’, inferences about what the fetus is characterised by apnea, cessation of fetal
may experience depend on interpreting sec- body movements and a shift to hypometabolic
ondary evidence. As discussed above, neuro- EEG states indicative of profound unconscious-
anatomical pathways necessary for processing ness.38 In the newborn, similarly threatening
pain, similar to those observed in adults and situations lead rapidly to full arousal, even in
older children, could be in place by 23 weeks the preterm neonate. In contrast to the buffered
gestation. The stereotypical stress response of fetal environment, the intense tactile stimula-
an adult or older child reporting pain is also tion of birth, the resulting separation of the
observable in the fetus at 18 weeks gestation. neonate from the placenta as a major source of
Behavioural reactions to noxious stimulation, com- in utero neuroinhibitors, and the onset of breath-
parable to the adult or older child, can be observed ing facilitate the usually rapid onset of behav-
from 26 weeks gestation. These and other obser- ioural activity and wakefulness in the neonate.
vations support the suggestion that the capabil- Birth marks the transition from laying down
ities of the fetal mind include an experience of brain tissue in the womb to organising that
pain from at least 26 weeks gestation.7,9,25 tissue with regard to the wider world outside
Inferring fetal pain based on these indirect the womb.
sources of evidence, however, presents notable A final obstacle to equating fetal pain
difficulties. The first difficulty is to account for experience with that of an adult or older child
the many features of the fetal brain that are not is the developmental process that begins imme-
similar to that of the adult and older child. The diately after birth. Theories of human develop-
cell structure of the immature brain differs from ment assume the early mind has minimal
that of a mature one, and the fetal brain has content that gradually evolves into the rich
several prominent structures that are transient and effortless experience of older children and
in nature. These structures likely regulate deve- adults.39–42 Although the view of a neonate as a
lopmental events in the womb that become blank slate, or tabula rasa, is generally rejected,
unnecessary after birth. The thalamic reticular it is broadly accepted that psychological pro-
nucleus, for example, appears as inconspicuous cesses have content about people, objects and
in the adult human brain but is prominent in symbols, which initially exist outside the
the fetal brain. In the fetal brain, a high packing brain.43,44 To uphold that the fetal mind has
density of neurons characterises this reticular direct access to pain, it must first be upheld that
nucleus, which undergoes cell death after birth. the content of pain is inherent to neural tissue
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available in the womb. That is, at some point and disease, but is a conscious experience,
during fetal development, there is developing modulated by mental, emotional and sensory
neural tissue directly coding pain experience. It mechanisms, with both sensory and emotional
must second be upheld that the developmental components. If this ‘‘multidimensionality’’ is
process, which enriches psychological experi- the basis of conscious pain experience, can we
ence, does not materially alter the pain experi- apply this experience to the fetus? If the fetus
ence coded directly into neural tissue. lacks the neural systems that support the cog-
nitive, affective and evaluative experiences
necessary for pain awareness, and anyway
The content of pain remains unconscious until after birth,38 then
Few living creatures do not respond to a noxious the answer is no. Reinforcing this conclusion,
stimulus, such as a pinch or a burning flame. the IASP definition further states that ‘‘pain is
Light a flame next to humble fruit fly larvae, for always subjective. Each individual learns the
example, and they will bend and roll away from application of the word through experiences
the flame.45 These responses are dependent on related to injury in early life’’.52 By this defini-
the presence of specialised sensory neurons, sim- tion, the neural tissue of the fetus at any stage of
ilar to the free nerve endings in humans, which development cannot support pain experience.
preferentially respond to stimuli with the poten- For this reason there have been attempts to
tial to cause tissue damage. The larvae clearly challenge and modify the definition of pain.47
have a biological apparatus to detect and respond There is good reason, however, to support the
to potentially dangerous stimulation but do they definition of pain as originally constructed. It
feel pain? allows us to define and understand pain as an
If pain is the response to noxious stimulation emergent property of social awareness, rather
then the answer is yes, the larvae feel pain. This than as a deterministic or spiritual phenomenon.
definition, however, would also mean that a
thermostat feels pain because it responds to
excessive heat by changing its internal state. The developmental process
By this logic, rocks might also feel pain as they Without consciousness, there can be a response
respond to excessive force by shattering. Indeed, to noxious stimulation, technically referred to as
interpretations of consciousness and pain that nociception, but there cannot be pain. Thus, to
view sentience or pain as an intrinsic quality understand how pain experience in particular
of life or nature lead to suggestions that larvae becomes possible, it is necessary to understand
and rocks have a conscious life.46,47 Such con- the origin and course of development of conscious
clusions, however, seem much too permissive. experience in general. It is reasonable to assume
Furthermore, defining pain based on response that conscious function can emerge only if the
may also lead to a tautological understanding of proper neural circuitry necessary to carry out
pain: pain is defined in terms of a stimulus con- that function develops fully and functionally.51
sidered to be painful because it elicits the pain Changes in frontal cortex activity, for example,
response. Put simply, pain is defined as pain.48,49 arrive when cognitively related behaviours, such
In other words, without an accurate definition as the phenomenon of stranger anxiety and
of pain the conclusion whether the fetus feels improvements in memory, begin to appear.
pain ends in circularity. An accurate definition Similarly the first coordinated motor movements
of pain is crucial. Definitions of pain that avoid require the further development of specialised
circularity usually include cognition, sensation motor regions of the brain.52
and affective processes, such as that provided It is also reasonable to assume that conscious
by the IASP (International Association for the function emerges only with suitable psycholog-
Study of Pain). The IASP have defined pain as ical content provided in a suitable environ-
‘‘an unpleasant sensory and emotional expe- ment.39–44 Sensations are not something that
rience associated with actual or potential tissue we experience raw and then interpret post hoc.
damage, or described in terms of such damage’’.50 The interpretation is the experience. Distin-
By this definition, pain is no longer regarded as guishing sensations from thoughts from emo-
merely a physical sensation of noxious stimulus tions requires a conceptual basis to allow the
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distinction. Neuropsychological development experience pain are things that arose within our
is more than hooking ‘‘alarms’’ to ‘‘buttons’’, it own brains by some individual biomechanistic
facilitates conscious experience. process such as neuronal maturation.39,44
For the development of neural connections This is not to deny the fetus and neonate have
and circuitry supporting conscious experience, the neural apparatus to discriminate infor-
birth is a critical event. At birth and afterwards mation. Clearly, the fetus and neonate do not
there is an increase in sensory input, which con- respond to tactile stimuli in the same way as
tributes to neuronal organisation. Repeated they do to auditory stimuli, for example. Indeed,
sensory input during this critical period of deve- this discriminatory processing is the raw mate-
lopment results in generation and stabilisation rial for a primary caregiver’s assessments of
of functional brain circuits and elimination of their infant’s needs and for the interactions and
disused and unused pathways.51 This internal behavioural adjustments that will occur in the
organisation of inputs is based on sensory input forthcoming months. Innate neural and behav-
that is external to the brain. ioural discrimination are part of the material for
Before an infant can think about objects or developing experiential discrimination, but
events, or experience sensations and emotion, experiential discrimination is yet to develop
the elements of thought must have their own and relies critically on interactions with a pri-
independent existence in the infant’s mind. This mary caregiver, as described previously. For the
is achieved via continued brain development fetus and neonate, these interactions are still
with discoveries made in action and in patterns to occur.
of mutual adjustment and interactions with the The experience of pain, understanding that
infant’s caregiver. The development of repre- I am in pain, demands that we formulate the
sentational memory, which allows an infant to experience as involving concepts – ‘‘sore’’,
respond and learn from stored information ‘‘stabbing’’, ‘‘damage’’, ‘‘threat’’, ‘‘body’’ – that are
rather than respond to material directly avail- themselves rooted in general beliefs that no fetus
able, is a building block, if not a cornerstone, of could have. We can be sure the fetus does not
conscious development. Representational mem- have a conceptual understanding of their sensory
ory begins to emerge as the frontal cortex circumstances because there is no medium in
develops between 2 and 4 months of age. From which to hold, challenge and adjust these con-
this point on there is the possibility of tagging in cepts.53 This problem extends beyond a mere lack
memory, or labeling as a ‘‘something’’, all the of language to express and individuate concep-
objects, emotions and sensations that appear or tual understanding to a recognition that there is
are felt. When a primary caregiver points to a no complex, segmented, mediated psychological
spot on the body and asks,‘‘Does that hurt?’’ they self that could harbour conceptual beliefs.
are providing content and enabling an internal Whether it is possible the fetus can sense a
discrimination and with it experience. This noxious event without understanding that I am
interaction thus provides for content and sym- in pain remains open to debate. There is a pro-
bols that allow the infant to locate and anchor found and profoundly important difference,
emotions and sensations. It is only in this way however, between knowledge about a sensation
that the infant can arrive at a particular state and sentience. The former is not merely reduc-
of being within their own mind. Although pain ible to samples of the latter as there is no fact-
experience is clearly individual, a process that based form of painful experience sitting inside
extends beyond the individual creates pain.39,44 the stimulus waiting to erupt inside the fetus.
This is likely to strike any reader as strange Over 350 years ago, Descartes demonstrated
because it is simply not how we intuitively feel that the eye is a kind of camera obscura that
pain to be. Because pain is automatic and per- inverts entering light. Although Descartes made
sonal we feel it to be both natural and private. marked steps in understanding physiology via
But the fact that we become able to experience a mechanical interpretation of bodily existence,
pain as a personal event does not mean that, in he rejected the idea that vision is merely the
the first place, we gained the ability to experi- effect of physical action in the eye and brain. In
ence pain entirely on our own. Nor does it mean the Second Meditation, Descartes explains that
that the psychological mechanisms by which we ‘‘perception is neither an act of vision, nor of
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7. SWG Derbyshire / Reproductive Health Matters 2008;16(31 Supplement):117–126
touch. . . but only an intuition of the mind’’.54 The survival and normal long-term neurodevelop-
orderly and calculable penetration of light rays ment.55 This is in distinction to the trajectory of
through the camera obscura exposes the light to some policy suggestions where the primary
the reason of the mind. The senses do not dazzle concern of the paediatric health care provider is
the mind. We may be sensorily immersed but seen to be treating the stress or pain experience.56
we do not drown or dissolve in sensation. Our Such an approach neglects the functional pur-
intuition of ourselves as particular things with poses of physiological stress responses to noxious
particular location and experience opens, rather stimuli, including, for instance, modulation of
than collapses, into our senses. Consequently, inflammation. Moreover and importantly, in at
even if an unknowable sentience can logically least some cases stopping pain is not the priority;
exist for the fetus, it is a mistake to suggest a rather it is preventing death and long-term com-
continuum or equivalence between passive sen- plications. A primary concern of preventing pain
sation and active experience. and stress during paediatric health care would,
By this line of reasoning alone, apart from for example, have blocked early efforts to cure
persisting fetal unconsciousness, the fetus cannot childhood leukaemia because the treatments were
experience pain. Not only do its biological exceptionally painful.57
development and state of neuroinhibition prevent Several centres have now begun to perform
it from experiencing pain, but the post-birth open and closed fetal surgeries for conditions
consciousness and environmental influences, such as lower urinary tract obstruction, hydro-
necessary to developing pain experience, are yet thorax, cystic adenomatous malformation of the
to occur. lung, congenital diaphragmatic hernia and large
sacrococcygeal teratomas.58 The possibility of
adverse effects on the fetus when it is undergoing
Clinical and policy implications: surgery dramatic neural development should temper
Earlier beliefs by paediatric anaesthetists that enthusiasm for use of analgesia and anaesthetic
neonates and young infants could not feel pain in the fetus undergoing such procedures. The
led to an under-utilisation of analgesic medi- possibility of adverse effects on the fetal environ-
cation in these populations.5,7 Before controlled ment that may disturb the conditions that
trials,4,5 however, there were reasonable con- promote normal neural development should also
cerns about intra-operative hypotension caused temper extrapolation from experiences with
by the anaesthesia of infants, and about post- premature infants to the fetus. It is tempting to
anaesthesia apnea and respiratory depression assume that what has been proven to be of clinical
that might result from narcotic analgesia. There benefit in the neonate will also be of benefit in
is now enough evidence that clinical benefits the fetus. However, the greater immaturity of the
outweigh risks from anaesthetic or analgesic fetus and its very different hormonal and physical
intervention during procedures on neonates and environment38 indicate that clinical trials should
infants, regardless of whether evidence supports be performed with fetal patients to demonstrate
or denies neonatal pain. Should paediatric anaes- improved outcomes. So far, there is no evidence-
thetists return to a view that the neonate and young based fetal anaesthesia or analgesia protocol
infant cannot feel pain, the clinical benefits of defined for these procedures.
anaesthetic intervention will remain. A lack of
pain experience provides no ethical or practical
reason to justify returning to a regimen of lesser Clinical and policy implications: abortion
anaesthetic or analgesic intervention, unless that The medical goals of survival and long-term
intervention itself were shown to be harmful. normal development of the fetal patient should
Accordingly, if evidence were to reveal that not influence medical decisions when the
introducing an anaesthetic or analgesic regimen patient is a pregnant woman seeking an abor-
undermines clinical outcomes then a presence tion. Under these circumstances, the need for
of pain experience may still be inadequate to fetal analgesia or anaesthesia can be directly
mandate use of that anaesthetic or analgesic addressed via an examination of the possibility
regimen. The major clinical outcomes that are for fetal pain and the effects of fetal pain relief
important to neonates and their families are for the health and well-being of the pregnant
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8. SWG Derbyshire / Reproductive Health Matters 2008;16(31 Supplement):117–126
woman. The case against fetal pain, as docu- not yet developed in the fetus at any gestation
mented earlier, suggests that a requirement to before birth. Evidence-based approaches that
provide fetal pain relief before abortion is not assess outcomes of greatest importance to the
supported by evidence of what is known about parents and the future of the fetal patient, sur-
the neurodevelopment of systems that support vival and long-term adverse consequences,
pain. Proposals to directly inject the fetus with should guide anaesthetic practice with the fetus
fentanyl,26 or to provide pain relief via increased during any procedure intended to benefit the
maternal administration of fentanyl and/or fetus. Current investigations of the possibility
diazepams can be rejected. These procedures for long-term negative outcomes from injury in
increase risks to the woman and costs to the early life should eventually provide evidence-
health provider, undermine the interests of the based guidance for such procedures in future.59
woman, and are unnecessary for the fetus who It is important to note that an absence of fetal
has not yet reached a developmental stage that pain does not resolve the question of whether
would support the conscious experience of pain. abortion should be legal. Debate over life, rights
and the sovereignty of a woman’s body cannot be
resolved with evidence of fetal immaturity that
Conclusion dictate the conditions of a clinically acceptable
We can be confident the fetus does not expe- abortion. Nevertheless, current evidence does not
rience pain prior to about 23 weeks gestation support efforts to inform women seeking abortions
because the neural circuitry for pain in the fetus of the potential for fetal pain. Any future legis-
is immature. More importantly the develop- lation to mitigate fetal pain could expose women to
mental processes necessary for experience are inappropriate intervention, risk and distress.
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Resume
´ ´ Resumen
La possibilite de la souffrance fKtale continue d’etre
´ ˆ Incrementar la posibilidad de dolor fetal continua ´
utilisee comme tactique pour miner le soutien a
´ ` siendo una ta ctica para debilitar el apoyo
´
´
l’avortement aux Etats-Unis et au Royaume-Uni. para el aborto en EE.UU. y el RU. En este
Cet article examine le developpement anatomique
´ artıculo se examinan los desarrollos anatomicos
´ ´
et psychologique du fKtus pour e ´valuer la y psicolo gicos del feto para determinar la
´
possibilite de douleur fKtale. Les caracteristiques
´ ´ posibilidad de dolor fetal. Las caracterısticas
´
neurobiologiques qui se developpent a 7, 18 et 26
´ ` neurobiologicas que se desarrollan a las 7, 18 y
´
semaines de gestation suggerent une experience
` ´ 26 semanas de gestacion indican una experiencia
´
de la douleur in utero. Ces caracteristiques ne´ de dolor in utero. No obstante, no se puede inferir
permettent cependant pas de prouver que cette dolor de estas caracterısticas porque no informan
´
douleur existe car elles ne rendent pas compte de sobre el estado de conocimiento del feto y no se
l’etat de conscience du fKtus ni du contenu d’une
´ les puede atribuir el contenido de una supuesta
perception presumee de la douleur. Il semble
´ ´ experiencia de dolor. Podemos estar seguros de que
assure que le fKtus ne connaıt pas la douleur
´ ˆ el feto no siente dolor porque los neuroinhibidores
car des neuro-inhibiteurs in utero uniques et unicos in utero y la falta de desarrollo psicolo
´ ´gico
un manque de developpement psychologique
´ mantienen la inconsciencia e impiden una
maintiennent l’inconscience et evitent l’experience
´ ´ experiencia consciente de dolor. Antes que un
consciente de la douleur. Pour qu’un nourrisson recien nacido pueda experimentar sensaciones y
´
experimente des sensations et des emotions, les
´ ´ emociones, los elementos de la experiencia deben
elements de l’experience doivent avoir leur propre
´´ ´ tener su propia existencia independiente en su
existence independante dans son esprit. Cela
´ mente. Esto se logra despues del nacimiento
´
s’accomplit apres la naissance par les decouvertes
` ´ mediante descubrimientos realizados en accio y ´n
faites dans l’action et les schemas d’ajustement et
´ en patrones de ajuste e interaccion con un
´
d’interaction avec la personne qui s’occupe de cuidador. Las recomendaciones sobre la practica´
l’enfant. Les recommandations sur la pratique de anestesica con el feto y el recien nacido o bebe no
´ ´ ´
l’anesthesie du fKtus et du nouveau-ne ou du jeune
´ ´ deben centrarse en el dolor sino en los resultados
nourrisson ne doivent pas se centrer sur la douleur, con importancia obvia y mensurable. En el caso
mais sur des resultats d’une importance evidente, et
´ ´ de un embarazo no deseado, la salud de la mujer
mesurable. Pour une grossesse non desiree, la sante
´ ´ ´ deberıa guiar la practica anestesica; en el de un
´ ´ ´
de la femme doit guider la pratique de l’anesthesie. ´ embarazo deseado, esta deberıa ser guiada por
´ ´
Pour une grossesse desiree, c’est la survie et la sante
´ ´ ´ la supervivencia y salud a largo plazo de la mujer
a long terme de la femme et du fKtus qui doivent
` y el feto. En todo caso, la evidencia actual no
la guider. Dans tous les cas, rien dans les donnees ´ corrobora los esfuerzos por informar a las
dont nous disposons n’indique qu’il faille informer mujeres del potencial de dolor fetal. Toda polıtica
´
les femmes de la possibilite de douleur fKtale. Toute
´ para mitigar el dolor fetal podrıa exponer a
´
politique destinee a soulager la douleur fKtale
´ ` las mujeres a una intervencio n inadecuada,
´
pourrait exposer les femmes a des interventions
` riesgo y afliccion.
´
indues, des risques et des souffrances.
126