Saturday, 13 October 2007

The abortion debate

The F Word reports that the abortion debate seems to be back. It is a disingenuous field where agendas are hidden and reasoning is often obscure and irrational.

I'm reminded of the debate over emergency contraception, involving many of the same faces, where, despite scientific evidence showing that it works by preventing fertilisation, not implantation, it is still opposed by religious groups who pretend that it is a form of abortion to hide their anti-contraception agenda.

There appears to be a growing acceptance in the public, driven primarily by the media, that the limit for abortion should be lowered below the current 24 weeks. The origin of this consensus is the coverage given to 4D ultrasound images of foetuses 'smiling' and 'waving' in the womb circulated by Prof. Stuart Campbell (the lack of interest in what stage of gestation these images were taken tells us much about just how rational this conclusion is - the 'smile' was apparently at 22 weeks gestation) and improved survival of preterm infants.

Actually they weren't smiling or waving at all but on a loop which made it look like they were. Which we shouldn't be surprised by since newborn babies don't smile until around 6 weeks of age (no, I'm sorry, that wasn't a smile, that was a grimace you saw in your newborn), and even then it is likely a reflex.

We can expect a lot of this sort of stuff to get another airing in the media, with the anti-abortionists having the best of it, because the public are pretty stupid, because the anti-abortionists use rhetorical sleight of hand, and because the pro-choice movement has traditionally shied away from engaging the scientific arguments head on, instead focusing on the 'right' to choose.

So what is the scientific evidence? For a start, the vast majority of abortions are performed before 12 weeks, and a tiny minority (under 2%) after 20 weeks before which many congenital abnormalities cannot be detected (the majority of abortions for congenital abnormalities incompatible with life such as anencephaly are performed after 24 weeks - the limit doesn't apply in these cases for obvious reasons), even in Britains slow and restrictive system.

I don't understand why the UK debate is framed in terms of viability, but before 22 weeks this is minimal, rising to 30% survival at discharge by 24 weeks where, of those admitted to neonatal ICU (54%), less than 5% survived intact (i.e. without major prematurity associated abnormalities), and even children born outside the 'grey zone' of foetal viability (22-25 weeks, the period where viability so low enough that it is controversial whether to initiate aggressive therapy) take a considerable hit in cognitive function when they grow up.

You'd think if people really cared about viability they'd press for making it easier to obtain an abortion early (such as removing the need to have 2 doctors approve), rather than trying to limit access, but funnily enough this doesn't seem to be their approach.

Despite all the crap about foetuses 'opening their eyes' propagated by Campbell, at 22-24 weeks the foetus does not have a connection between the retina and the cortex, so isn't able to 'see' anything, similarly, while peripheral pain pathways are present by 10-15 weeks, and spinal pathways by 20 weeks, cortical innervation is not present until around 24 weeks, and functional responses in cortex by around 30 weeks i.e. noxious stimuli just don't get to the bits of the brain that mediate the perception of pain until the baby reaches term.

Anti-abortion campaigners like to pretend it is about the science, and that is how they seem to have successfully framed the latest 'debate', but that's bollocks, its about having the most effective rhetorical devices for them - that is why they only focus on the 'evidence' that is emotive and sways the ignorant public, rather than seriously engaging with the science - here's Campbell:

"Pain is a very difficult thing to measure in an unborn baby. Foetuses have no memory of pain, and no anticipation of it. But if you stuck a pin into a foetus, I believe it would make a crying face and flinch. Clearly, that's an experiment we can't carry out, but we can weigh up the evidence we have and make the best judgment possible.

Babies born at 22 weeks are never treated without analgesics. Why, if there is scientific evidence to prove their brains are too under-developed to feel pain or distress, would they be given medication to protect them from pain? And if we accept that these babies may feel pain, why is it so difficult to imagine they would feel the same sensation inside the womb?"
Why indeed? Perhaps because we know that peripheral pathways can be damaged or sensitised even without central pain being perceived*, and that hormonal stress responses can be activated even without cortical activation, which could have physiological repurcussions later in life.** Disingenuous bastard trying to gloss over the science with ill-posed rhetorical questions - and this is only the start of it. There's plenty of scientific misrepresentation to come.

* Compare with phantom limb pain in people who have their limbs amputated. Damage to the nerve endings causes sensitisation and leads to persistent pain after the surgery, despite no pain being felt under general anaesthesia during the procedure itself.

**Pain pathways to subcortical structures could also still represent pain perception on a parr with that of 'lower' animals, even if not of the sophistication of fully grown humans, which is a consideration for those of us of a more utilitarian bent.

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