The hot topic at the moment is the recent “repeal” of Roe v. Wade by the US Supreme Court. This topic involves not only legal, but also moral, social, and scientific issues. This blog being a science blog, it’s appropriate to comment on the scientific issues here, and to that end I have produced the chart of human prenatal development above. Horizontal bars show fetal size on a logarithmic scale, and the two images are from Wikimedia and from USAID. Confusingly, two time scales are in regular use for prenatal development, one starting at the last menstrual period, and the other at fertilisation (around 2 weeks later). The chart shows both.
Roe v. Wade had, in fact, largely been overturned by Planned Parenthood v. Casey in 1992. The majority of people in the US (around 63%) believe that abortion should be legal in some cases but illegal in others (although views vary widely between demographic groups and from state to state). Roe v. Wade claimed a constitutional right to an abortion based on a constitutional right to privacy, and attempted to draw a cutoff for abortion legality based on the trimester of pregnancy:
- “For the stage prior to approximately the end of the first trimester, the abortion decision and its effectuation must be left to the medical judgment of the pregnant woman’s attending physician.
- “For the stage subsequent to approximately the end of the first trimester, the State, in promoting its interest in the health of the mother, may, if it chooses, regulate the abortion procedure in ways that are reasonably related to maternal health.
- “For the stage subsequent to viability the State, in promoting its interest in the potentiality of human life, may, if it chooses, regulate, and even proscribe, abortion except where necessary, in appropriate medical judgment, for the preservation of the life or health of the mother.”
Planned Parenthood v. Casey rejected both of these ideas, grounding a right to abortion instead in the due process clause of the 14th Amendment (“nor shall any State deprive any person of life, liberty, or property, without due process of law”), and drawing a new legal line solely based on viability (the age at which the unborn baby can survive outside the womb) rather than on “Roe’s rigid trimester framework.”
The Supreme Court of the United States: the Roberts Court
Viability has some appeal as a guideline, since many people consider it problematic to kill an unborn baby which could be delivered by caesarean and then cared for successfully in the neonatal intensive care unit down the hall. However, as the recent judgement by the Roberts Court in Dobbs v. Jackson Women’s Health Organization notes, viability “is heavily dependent on factors – such as medical advances and the availability of quality medical care – that have nothing to do with the characteristics of a fetus.” In fact, the viability threshold has been dropping at around a week per decade, sitting now at around 22 or 23 weeks (see the chart). Dobbs also took issue with the constitutional aspects of the decision in Casey, overturning it (and what was left of Roe), so that “the authority to regulate abortion is returned to the people and their elected representatives.” Some of “the people” have been very happy about this, while others have protested.
Another scientific (or rather, technological) issue relevant to the decision in Dobbs has been the widespread use of obstetric ultrasonography in the United States. Janelle Taylor notes that “the obstetrical exam has come to incorporate rituals of showing and telling and giving out pictures” (we have all seen them on Facebook). Such images have greatly influenced how the fetus is viewed by the population at large. Unsurprisingly, such images have also lent support to pro-life campaigners, since they give a very clear face to the unborn. This article in The Atlantic notes that “in recent years, pro-life activists have been more successful in using that tool [scientific evidence] to shift the terms of the policy debate.”
More complex has been the debate on whether the unborn human can feel pain. Even in adults, pain is complex, with two separate human pain systems, one more precisely localised, and the other more affective (it “hurts” more). No real scientific consensus currently exists on when a fetus can feel pain (indeed, how could you really prove a hypothesis here?). Various stages are reported in the literature, some as early as 14 weeks, and this literature has been heavily cited as part of the ethical debate on abortion. Other writers have, rather disturbingly, suggested that only adult human beings can truly feel pain. The debate in the US and elsewhere is ongoing.
Scientific Gems 