Science and Abortion

t is the nature of a democratic society that the masses are entitled to make decisions for themselves, and their punishment is that they have to live with them. Still, it's strange to see people becoming hysterical over the right to do something they say they don't want to do.

Many arguments have been made for and against abortion. They may be useful for stirring up outrage, but they are also irrelevant. There are only three relevant facts: (1) is the fetus a human life? (2) is it a separate individual deserving of consider­ation? and (3) at which point in its development does it come to deserve the right to survive?

There is no doubt about questions (1) and (2). Science tells us unequivocally that an individual human life begins at the moment of fertilization. This means a fetus at some point acquires a legitimate interest in survival that needs to be taken into consideration.

Abortion rates in the US are slowly returning to historic pre-Roe norms

When someone says they are “for” or “against” abortion, they are making an absolutist statement. Absolutist arguments prevent a solution by generating fear that one's opponents will impose an extremist ruling on the other. It is incumbent on us to use rational arguments, not absolutist, unsound, or self-serving ones, and to base decisions on empirical facts. This is why a recent editorial at Nature magazine is so disturbing.

The pro-abortion / pro-choice arguments

The Nature article alludes to health care and equality as their primary arguments.

1. The equality argument: “Equality,” as described in the Nature editorial, means “women's equal participation in society,” which is to say their economic well-being is impaired by raising children. Indeed, it costs money to raise a baby, and this cost is clearly higher for a parent who does not have an abortion. It can result in financial hardship, a reduced credit rating, future college expenses, and possibly bankruptcy.

2. The health care argument: The second argument is that preventing abortion would result in “increased health problems for babies and often for mothers, for several reasons—including reduced prenatal care.” They cite a study saying that the lifetime risk of dying from pregnancy-related causes for black women would increase from 1 in 1,300 to 1 in 1,000 if abortion were ‘eliminated.’

This is a good argument, if one were needed, for reducing the risks of pregnancy-related death. But it is hardly an argument for abortion. The woman's risk rises from 0.077% to 0.100%, but the fetus's risk rises to 100%. So it's really an assertion that the fetus's life is unimportant compared to the parent's. It's also an absolutist argument.

One cannot ignore that being dead is also a health problem for the fetus, in fact a rather serious one, and needs to be taken into consideration.

Some other popular arguments are clearly invalid.

3. The coat hanger argument: This one says that women would go into back alleys and use coat hangers if they could not obtain abortions. It's easy to refute by analogy: we know that people commit murders in various unpleasant ways, even by using coat hangers, yet we don't make murder “safe and legal” because it would be absurd.

4. The personal autonomy (“choice”) argument: Proponents often say “My body, my choice.” But there are two bodies involved, each with a legitimate interest. Both deserve consideration. So this argument is invalid.

5. The get-rid-of-the-damn-left-wingers argument: A few people say that pro-abortionists have other beliefs that threaten civilization, therefore abortion is beneficial because it reduces their number. Ideology is not inherited, so this argument, while tempting, is not valid.

The anti-abortion / pro-life arguments

1. The sanctity of human life argument: If no human has the freedom or the right to kill another, then that prohibition should apply to the unborn as well. Not everyone opposes a ban from the moment of conception; many are willing to defer to a scientifically established demarcation point, such as the point where it can feel pain.

Some pro-lifers believe that the combination of genes in a fertilized egg is sacred and therefore all abortion should be banned. As a biochemist I appreciate their admiration for DNA, but the view that human DNA is sacred would prohibit gene therapy.

2. The legal uniformity argument: This argument says that abortion laws in the USA should be made consistent with each other and with western Europe, where they are much more restrictive. This is a legalistic argument.

3. The incentivizing death argument: Live cells from aborted fetuses are widely available to scientists from companies that buy them from abortion clinics and sell them for a profit. Those who don't use them are at a competitive disadvantage. Thus, incentivizing death seeps into every part of society, even science. This argument appeals to the discomfort some people feel in selling body parts and compares abortion to harvesting of organs from prisoners as is done in some countries.

When does the fetal human brain experience pain?

With that in mind, let's examine the scientific evidence. Much of the scientific debate centers on pain and whether it depends on thalamocortical connections. These are neuronal connections between brain cells in the thalamus (a lower part of the brain) and the cerebral cortex, where thinking occurs. The cortex is often defined as "gray matter" and the connections between brain cells are called "white matter" because they are covered with white insulating material called myelin.

There is clear evidence for cortical gray matter at least by 16 weeks. A landmark mega-author summary of MRI data ^[1] showed that cortical gray matter volume increases dramatically starting at 16 pcw (post-conceptual weeks), or about mid-gestation, peaking at 5.9 years. White matter increases rapidly from mid-gestation to 28.7 years. There are no MRI data for earlier than 16 pcw.

According to Kadic et al. ^[2], the fetus processes sensory stimuli including pain from about 25 weeks. By gestational week 34 it can perceive external sounds and discriminate sounds. Fetal action planning occurs by 22 wks. Sekulic et al. ^[3] argue that the fetus could be more prone to pain than adults because the structures for pain are formed by the 12th to 14th week while the pathways that block pain (inhibitory descending serotonin pathways) mature only after birth. Substance P, a peptide used to transduce pain signals, is present in the brainstem nuclei by the 11th to 12th week. They also note that there are other things besides pain:

The reaction to touch begins during the 7th week of gestation when touching the peri-oral area results in the head turning away.

Many studies assume that consciousness, which is generally thought to occur in the cerebral cortex, is necessary to feel pain. Derbyshire ^[4] concludes that the fetus does not feel pain at all because it is “unconscious.” Lee et al.^[5] say the capacity for functional pain perception “probably does not exist before 29 or 30 weeks”, so anesthesia is not required during abortion. However, Rokyta et al. ^[6] point out that potentially painful stimuli could have an adverse effect on development even in the absence of consciousness:

Cortical processes occur only after thalamocortical connections and pathways have been completed at the 26th gestational week. Harmful (painful) stimuli, especially in fetuses, have an adverse effect on the development of humans regardless of the processes in brain.

The question of whether the fetus is conscious or not is very hard to determine scientifically because it is difficult to agree on a definition of consciousness and even more difficult to measure it.

Thill ^[7] argues that fetal pain is possible during the first trimester (<14 weeks):

The neural pathways for pain perception via the cortical subplate are present as early as 12 weeks gestation, and via the thalamus as early as 7–8 weeks gestation; (2) the cortex is not necessary for pain to be experienced.

By contrast, Lagercrantz ^[8] thinks if we assume consciousness requires the cerebral cortex, it could not emerge before 24 wk when the thalamocortical connections from the sense organs are firmly established.

It is likely that some of these studies are motivated by a desire of practitioners to avoid lawsuits or by ideological factors. More research is needed to refine the timeline. Nevertheless, given these uncertainties, it might be prudent to err on the side of caution, as other countries have done.

may 08 2022, 6:50 am. updated may 09 2022