Jeanette Forsyth BSc Psychology. Please do not copy without referencing. Subject to copyright.
Pain and the developing child: looking at the foetus.
International Association for the Study of Pain (IASP) description of pain is: “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”
Pain in new born infants is clearly seen, there are physical physiological reactions as well as emotional reaction through the sensory experience; the cry, the bulging eyes, the tears, the high pitched scream, the withdrawal. What about the infant you can't see; The growing developing foetus what is their reaction to pain? Infants delivered at 26 weeks clearly show signs of pain (Craig et al 1993).
The foetus makes withdrawal reflexes in reaction to cutaneous stimulation, these are observable in the gestation developmental stages (Humphrey 1978). However these do not imply effective pain perception, due to them not being specific to nociceptive stimuli (a receptor of a sensory neuron (nerve cell) that responds to potentially damaging stimuli by sending signals to the spinal cord and brain). The foetus responds but it is not deemed to cause the perception of pain. However Structual connectivity has been confirmed in ultrasounds, synapse movement between sensory neurons and interneurons and motor neurons at only 5-6 weeks gestation. By 14 weeks most of the body surfaces can evoke a reflex response (Okado 1981). What is not known at this stage if pain can be felt in any capacity, the assumption is they can't.
We know stress response symptoms show increased blood flow, increased heart rate and rise or drop in the respiratory rate. We also know that neuroendocrine changes (neurotransmitters released by nerve cells releasing hormones into the blood thus being an integration of the nervous system and endocrine system) changes with increased production of catecholamines, cortisol, and other stress hormones, increased beta-endorphin and noradrenaline releases (Adaes 2014). Stress responses can be observed in the early part of the second trimester 13-28 weeks.
We know parental stress hormones and cortisols have an impact of the unborn child. We know that the perinatal time is a sensitive one and there can be reactions with Mothers who have been under high stress in her pregnancy, suffered trauma in her pregnancy or suffered perinatal depression or mental health in the pregnancy. The emotional damage that can be done should not be underestimated however there is little evidence that it causes actual physical emotional pain to the foetus. It suggests it has impact on the chemicals and hormones involved in brain wiring.
These are not seen necessarily by scientists indicative of physical pain perception but we do have to query emotional pain perception. The thought is that the emotional component of pain entails the need for consciousness, to allow the recognition of and meaning of; an unborn child is not deemed conscious of it because it's not been consciously categorised and labelled. We know by differing cries there is a sharp shrill cry that is linked to pain so we are aware that babies feel pain and respond to pain on delivery, this has been seen for babies at delivery 24-26 weeks.
Currently in order for a stimulus to be perceived as painful, a whole circuitry system has to be fully developed and functioning. This meaning information must travel from spinal cord neurons, whose axons project to the thalamus, which sends afferents to the cerebral cortex. From research available and within its limitations, it has determined functional sensory fibres and spinal reflexes can be found by 20 weeks of gestation, as well as connections to the thalamus. Though the sensory fibres are functional and spinal reflexes are found it is not seen as having the possibility of ability of pain. This pathway however becomes fully functional in the third trimester, around 29 to 30 weeks gestational age, when mature projections from the thalamus to the cerebral cortex are present (Adaes 2014). This suggesting from 20 weeks to 30 weeks gestation the foetus has ability or starts to have the ability and feel physical pain.
This obviously poses new questions for foetuses that are aborted after 20 weeks as it is generally agreed that the minimal necessary neuronal pathways for pain are in place by 24 weeks gestation. Under UK law, an abortion can usually only be carried out during the first 24 weeks of pregnancy as long as certain criteria are met. The Abortion Act 1967 covers the UK mainland (England, Scotland and Wales) but not Northern Ireland. There are however exception to this rule. However we are having surviving infants from 20 weeks which then poses an ethical question on the abortion age. “The District of Columbia Pain-Capable Unborn Child Protection Act,” H.R. 3803, is based on medical and scientific findings that the unborn child at 20 weeks and beyond is capable of feeling pain, and may even be more sensitive to pain at that point than newborns are. Professor Malloy told a committee “Moreover, the fetus and neonate born prior to term may have an even heightened sensation of pain compared to an infant more advanced in gestation,”
This could be backed up by Research done by Nicol (et al 1998) and Crossley (et al 2000) have found that the GABA receptors ( GABA helps to control the fear or anxiety experienced when neurons are overexcited by inhibiting them) are suppressed and rise in levels in gestation and before birth. This suggesting that it acts as a mild psychological suppression to the foetus central nervous system reducing sensory responsiveness.
Lower levels of GABA are linked to anxiety. Crossley (2000) says there is Steroid modulation of the GABA(A) receptor in the fetal brain which is likely to have an impact on the developing foetus; influencing the foetal Central nervous systems activity in late gestation. It is thought that the GABA receptors go from excitatory to inhibitory activity during a vaginal delivery. After delivery baby and mother (Maternal care) is most important as the oxytocins is crucial for the balancing of the brain, physiology and emotional responses of the baby to subside. Interferences from external source can cause an imbalance (Levin et al), the mother and child do not get balanced.
Recently a baby delivered was certified as dead after delivery. Parents in grief wanted to have their child placing on the mothers chest. The baby revived and came around, this suggesting that the maternal baby connection is more powerful than people think as well as providing the natural baby environment (kangaroo care). The touch and the sound stimulation of the mother being the first sensory systems being re-engaged after birth.
This suggesting that the human foetus has it's own complex system in managing pain in the third trimester unless there are complicating external factors that impose into the foetus's environment; high stress cortisols from mothers environment or mental health, trauma impact, drugs, alcohol and smoking to name a few. However there must be caution in the second trimester as the physiology is present but we are still unaware if the cortex only is needed for pain awareness or if the primal systems linked up to the thalamus feels pain. The foetus does not seem to have the same protection of the GABA inhibitory in the second trimester thus concluding that it is possible that the foetus will and can feel pain.
References
Adaes. S. (2014). Foetal Pain – When Does Pain Become Pain Psychology latest AUG. 5, 2014
Craig (1993)
Crossley (2000)
Levin. R. (2010) Chapter 20 in Ritsner M.S. Brain Protection in Schizophrenia, Mood and Cognitive Disorders.
Humphreys (1978)
Nicol (1998)
Malloy (2012)
http://www.lifenews.com/2012/05/25/neonatology-professor-unborn-babies-feel-pain-at-20-weeks/ accessed 5/7/2014.
Toates.F. (2007). Biological Psychology. The Open University.
http://www.iasp-pain.org/ accessed 05/07/2014.
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