New Scientist 1 Nov 97
HUMAN fetuses cannot feel pain at the stage in pregnancy when most abortions are carried out, according to a panel of British experts. The panel, set up by the Royal College of Obstetricians and Gynaecologists, says that pain is impossible for the first 26 weeks of pregnancy-roughly the first two-thirds of gestation. But this conclusion has raised concern among some scientists, who argue that pain may be felt earlier. In Britain and the US, more than 90 per cent of all terminations are carried out in the first 14 weeks. It is not until 12 weeks later, the report says, that pain becomes possible, after the development of key nerve connections from primitive midbrain structures to the brain's cortex. The authors write: "Awareness is a cortical phenomenon. It follows that fetal awareness of pain is impossible until the time that sensory connections first penetrate the cortex." To avoid any chance of fetuses suffering pain, the report recommends that doctors consider using analgesia and anaesthetics in tests or surgery on a fetus more than 24 weeks into pregnancy. This coincides with the legal limit for abortions in Britain, except in rare cases where termination is necessary for medical reasons. A bitter debate has raged in recent years about when awareness of pain might begin ("Into the mind unborn", New Scientist, 19 October 1996, p 40). Opponents of abortion claim pain is possible within a few weeks of conception. The earliest limit accepted by some scientists is 13 weeks, when signs of electrical activity become visible above the brain stem. Some are concemed that the new report has drawn a firm line at a much later date. Vivette Glover, an expert on the biology of stress at London's Queen Charlotte and Chelsea Hospital, says: "The conclusions are much too strong and definite." She says there is evidence that pain neurons make temporary cortical connections from 20 weeks. Glover believes that the awareness of pain evolves gradually from this stage. David Concar
"Into the mind unborn" - A Summary New Scientist 19 October 1996, p 40
Premature babies can be kept alive from as young as 24 weeks. There is thus a significant overlap between late fetuses and early infants. It remains unclear to what extent reflex reactions or incresed hormone levels indicate a subjective experience of pain.
"Having never spoken to a fetus, I can't say what it feels, but I am deeply suspicious of the motives of people who ask me".
The Silent Scream ultra-sound inages of the supposed agony of a 12-week fetus being aborted.
Abortions past 20 weeks constitute only 1.3% of abortions, but these frequently involve dismemberment of a 22cm long fetus often but not always dead at the critical point.
Certain procedures such as inserting a needle into the fetus to treat maternally-induced anaemias at 19 weeks have been found to induce 3-fold increases in cortisol and a 5-fold increase in beta-endorphin, increase of nor-adrenaline and increase of blood to the head. However these changes are not necessarily accompanied by pain or conscious reaction in adults.
The exaggerated reflexes of 26-week old fetuses may indicate gross physical reaction in the absence of conscious awareness, rather than sentiant pain.
The first sign of any electrical activity above the brain stem occurs at about 13 weeks. Vivette Glover, who controversially to the abortion debate, administers sedation to fetuses suggests that fetuses may have "an evolving level of consciousness from the beginning of the second trimester". However Maria Fitzgerald points out the connectivity is relatively undifferentiated at this point with many pervasive connections throughout which do not have focussed domains of sensitivity. There is no evidence specific pain fibres have grown into the spinal cord at 19 weeks, although this may be due to experimental difficulties with small fetus neurones.
The subjective experience of pain in adults requires not only sensory pain fibres but a coordinated reaction from several brain centres including the somatosensory, cingulate and frontal cortices. Stuart Rosen suggests from heart patients responses that frontal involvement is essential for pain to be recognised as such. Nerve connections between the cortex and thalamus pivotal to active cerebral function begin to form at around 22 or 24 weeks and the first measurable sensory nerve impulse triggered excitation takes 29 weeks.
Other researchers take the irksome view that pain cannot be experienced until we have memories and experiences to relate sensations to - making the case that a fetus cannot 'feel' because it has no experience of life. However fetal pain could alter the growth pattern of key neural structures - a case which those using fetal painkillers respond to - however birth itself is painful to the infant and a stimulus to begin breathing and start the difficult process of living with gusto.