We Know Abortion-the-Politics. What About Abortion-the-Science?

Abortion rights are largely argued in terms of beliefs derived from religious convictions or political philosophy: a fetus’s “right to life” versus a woman’s “right to choose.” The rights themselves are defined and interpreted as laws that have binding effect on personal behavior. Although activists for life and choice are more driven by belief than by the spirit of scientific inquiry, new information derived from scientific research has the power to inform, and eventually to change, the terms of the arguments, and therefore to affect the laws and their consequences.

How might science impact how abortion is practiced and regulated in the United States in the post-Roe era? One way is through improved understanding of fetal consciousness. Here’s how that might work, beginning with some basic data.

Depending on who’s counting (Centers for Disease Control and Prevention or Guttmacher Institute), between 630,000 and 930,000 abortions are performed annually in the US, down from a 1980s peak of about 1.6 million. Nearly all abortions in the US happen in the first half of pregnancies: 93% within the first 13 weeks and only 1% after 20 weeks (CDC). Very few abortions are performed in the third trimester. Women who seek them out usually do so based on information learned later in their pregnancies — high risk to themselves from a full-term pregnancy, fetal abnormalities that would make life brief and/or severely impaired for the baby if born, radical change in their life circumstances, etc. A third-trimester abortion typically costs $1,000 or more; it’s a significant medical procedure for which there are relatively few providers.

Though few in number, late abortions are emotionally potent and hence featured in anti-abortion campaigns, because some of these abortions involve ending the development of a fetus which bears increasing resemblance to a baby, rather than a tiny mammalian embryo. Although a clear majority of Americans believes that the protections of Roe v. Wade should not have been overturned, support for late abortions is much lower. Roe’s standard — viability — appeals to the broadly popular belief that abortion should be simply legal early, but harder to get later. The problem with viability as a standard, however, is that it is a moving target. Roe’s viability benchmark says that state laws may limit abortion after the point in a pregnancy when prematurely delivered infants could survive outside the womb. This standard has always been somewhat imprecise and has become more contentious over time. In the future the problem will only get worse, complicating any effort Congress or individual states might make to save the protections of Roe v. Wade in legislation.

In 1973 when Roe was decided, few babies born before the end of the second trimester would survive, and few doctors would even try. In the 50 years since Roe was written, medical advances have pushed the frontier of viability earlier and earlier. At least one 21-week-old newborn is known to have survived, and many advanced neonatal facilities now try to save preterm births at 24-28 weeks, with about a 50% success rate. A medical technology company in the Netherlands plans to bring an artificial womb to market in about five years, which would make it possible to sustain fetuses in a very pre-birth-like environment from as young as 21 weeks, floating in a synthetic amniotic fluid, sustained through an artificial placenta. A 21-week-old fetus weighs less than a pound. Could this become the new viability benchmark? Since this artificial womb is a technology product, it’s amenable to improvement; will Version 2.0 work for 18-week-olds, and Version 3.0 for 15-week-olds?

If viability is becoming a less workable standard, what are the other options? There is, of course, the pure “choice” model, which argues that a woman’s right to choose to have an abortion should be absolute and unconditional at any time during her pregnancy, but public support for this is much lower than for a standard that sets some late-term conditions. At the other extreme, abortion opponents offer at least three draconian limits: conception, implantation, and heartbeat, none of which are popular outside their own hardcore ranks. There is also an argument (enshrined in the laws of 22 states) based on when a fetus can experience pain. In many states, these laws bear no relationship to the scientific understanding of how fetal perception of pain works. Another proposed standard is degree of brain development. With enough understanding of brain development, it would be possible to correlate abortion policy decisions to the pregnancy calendar much more consistently than the viability standard allows.

The most important achievement of brain development for purposes of this discussion is the creation of consciousness. Before the emergence of consciousness, a developing fetus has no awareness of itself or its circumstances, and no capacity to construct the experience of pain from negative stimuli, because pain needs consciousness to be perceived. For many pregnant women, abortion is a more bearable choice if it is clearly not inflicting pain or emotional distress on a conscious being. Consciousness isn’t a simple benchmark, but, unlike viability, it is not subject to radical change through better obstetric technology.

For the minority of Americans who believe that personhood begins at conception, implantation, or heartbeat, the differences between viability and consciousness are irrelevant — it’s all murder. For the majority who believe that abortion should be a legal but not unlimited option for pregnant women, the capacity of the brain to achieve consciousness could be a workable replacement for viability.

Scientists have learned a lot about consciousness over the past few decades, although there’s plenty more to learn. First, it exists on a continuum — humans can be alive but completely unconscious, or have minimal consciousness, or basic consciousness, or more-or-less full consciousness. We’ve learned that the brain needs to be running continuously to support consciousness, and that a person needs to be both awake and aware to be conscious. For example, a person in a coma is neither awake nor aware, but a person in a vegetative state can be awake but not aware, and therefore still not conscious. Likewise, a fetus can be measured going through cycles of being awake and asleep, yet not be conscious.

The brain begins as a small cluster of cells a few weeks after conception and is built out over the rest of the pregnancy and well beyond — brain development continues into early adulthood, as the parent of every teen knows. The small cluster of cells which emerges at the top of what will become a spinal cord early in a pregnancy is not yet even a remotely conscious brain; it has no awareness of anything, let alone awareness of itself as a future sapient person. This initial collection of cells is not completely unlike the self-organizing “cerebral organoids” grown in labs to study brains. It cannot be aware of its own loss should it be aborted or simply fail to implant. As the brain develops from an unconscious clump of cells to a structure that increasingly resembles a newborn’s brain, how and when does consciousness emerge, and how could its emergence influence our thinking about abortion?

In the early weeks of pregnancy, a tiny human embryo is barely distinguishable from the embryos of many other species. Fetal electroencephalograms — known as EEGs — show brain electrical activity from about 20 weeks onward. Most of the initial building blocks of the neocortex, the part of the brain most uniquely human, are not in place until about 26 weeks, and at that point they are still not very connected to each other or the rest of the brain and body. Between 24 and 30 weeks a lot of neocortical wiring happens through the thalamus, creating increasing potential for consciousness, but not consciousness itself. The hippocampus, also a contributor to consciousness, gains most of its cells between weeks 22 and 32.

The wiring project can only go so far before birth, because sensory input from the world outside the womb is an essential resource for the wiring and pruning process which develops the capacities of the brain. Until separated from the placenta at birth, a fetus is subjected to very low oxygen levels (equivalent to breathing at the top of Mount Everest) and a cocktail of maternal hormones which keep the level of metabolic activity below that characteristic of a conscious brain. At birth, an extraordinary physiological ballet cuts off the hormones, flips the role of a key signaling molecule, and floods the brain with oxygen, rapidly activating basic consciousness. A full-term newborn is awake, typically, for about two hours until the rush wears off, and then sleeps most of the time for the next several months.

Even at birth a full-term newborn is not nearly as conscious as it will be a few months later: it has only a few seconds of short-term memory, very low-resolution visual and aural senses, and a minimal sense of itself. It has reflexive behaviors such as making eye contact and hunting for a nipple, but these are more instinctive than thoughtful. Human brain development is so complex that it takes decades. The human gestation period — 280 days — is nearly 100 days longer that the average gestation period for other mammals our size. That extra 100 days is mostly needed for brain development, and even at that, giving birth as soon as possible is necessary to just barely get the newborn’s large head through the birth canal. It appears that we’re born just as soon as our brains are put together enough to be jolted into basic consciousness at birth.

An extremely pre-term infant, fighting to survive in its incubator and fiercely loved by its parents, is far less conscious than the parents might imagine. In fact, being prematurely deprived of the quietude of the womb and subjected to the vastly greater stimulations of the world outside the womb may contribute to the higher rate of neurological disorders that extremely pre-term babies experience later in life. As difficult as it is for us to accept, if that tiny newborn dies, it does not experience its own death at all the way a fully conscious adult or child would. Its brain is not yet capable of more than minimal self-awareness. It has reflexes, but not reflection. It induces a strong emotional response in loving parents, but it is not experiencing its life anything like the way they are experiencing theirs. We project adult mental processes onto babies just as we do onto pets, for understandable reasons. If it lives, it gains consciousness (of the newborn kind) around the time that it would have been born full term, and then joins the rapid march to higher consciousness over the next four months, and the longer march over the next 25 years.

For women who must decide whether to proceed with a late abortion, it may be reassuring to know that the brain of the fetus they carry is likely to be incapable of more than minimal awareness before getting a powerful wakeup call during the birth process. This is not to say that it is not a very fraught and sad experience for a woman to choose a late abortion, but it is perhaps not a fraught experience for the fetus. This is not an argument for delaying abortion decisions any longer than necessary — if it’s going to happen, the sooner the better for the mother’s sake — but if an abortion is performed relatively late in pregnancy, it seems unlikely that the fetus is made to consciously experience its own end. Using consciousness as a standard would make it easier to confirm that “life of the mother” and “severe fetal abnormality” reasons for abortion can be applied throughout most of a pregnancy. Over time, scientific research will further refine our understanding of fetal consciousness, and support refinements in policy. The use of a fetal consciousness benchmark could make it easier for states to establish stronger support for a woman’s right to choose over a longer proportion of a pregnancy’s span and inform whatever limits they choose to set.

Even though a fetus is apparently unconscious or minimally conscious until nearly the hour of its birth, there is still the ethical question of how to weigh its interests as a soon-to-be-here person against the interests of the mother as an already-here person. This issue is as ancient as the origin of our species. Homo sapiens evolved two unique traits at roughly the same time: bipedal locomotion and fancy brains. Our hind-legged locomotion was vastly more efficient than four-footed perambulation (and freed up our forepaws to do handy things), but the pelvic architecture it necessitated made giving birth to large-headed babies difficult and risky.

Our fancy brains also take an exceedingly long time to wire up: as mentioned above, human gestation is nearly 100 days longer than that of mammals of comparable size to allow for just part of all that wiring, and then the resulting child is dependent on its parents for years while brain development continues. When a human female becomes pregnant therefore, she is facing a remarkably long period of high risk and major commitment of resources — far longer than she would in any other species. For her genes, the opportunity cost if she bears a child that never reproduces is extraordinarily high.

It should not be surprising that our species barely survived this Rube Goldbergian evolutionary scheme: the genetic record shows that Homo sapiens apparently shrank to as few as 1,000 individuals about 70,000 years ago, and by the time agriculture emerged 10,000 years ago, global human population was still only a few million. It climbed slowly to 600 million in 1700, and then began to accelerate, reaching a billion a century later. Recently we’ve been adding a billion every 12 years. The population explosion of the past two centuries, in light of the vastly long period of almost no growth, is perhaps the most surprising thing that’s happened in the history of our reproduction-challenged species. The bets on bipedal locomotion and big-time mental faculties eventually paid off, but they nearly killed us first, and still may if we don’t tackle the climate crisis a lot better than we have been.

Our evolutionary path has rewarded apparently contradictory behaviors: on one hand, since pregnancies and extended child-rearing are high-risk endeavors that often fail, hunter-gatherer tribes tend to pursue every opportunity to successfully run the gauntlet and bring another child to reproductive adulthood. Healthy women of child-bearing age are a precious resource, and if a tribe loses too many, or if they have too few children, the tribe faces extinction. Not surprisingly hunter-gatherers reward and protect child-bearing women, and also “persuade” them to get started on childbearing as soon as they are able. Just this month, according to CBS News, a 25-year-old herdsman in South Sudan traded 60 cattle for a 14-year-old bride who left school to help feed her starving family by marrying for meat on the hoof, so this remains a current practice.

On the other hand, given the magnitude of risk and the dedication of time and effort required to conceive, bear, and raise each child, a woman has relatively few chances to do so in her lifetime, and therefore should not waste pregnancies on long shots and bad bets. This is the underlying evolutionary logic of a woman’s right to choose. The tension between tribal best reproductive strategies and each woman’s personal best reproductive strategies has remained unresolved through the invention of agriculture, the rise and fall of empires, the establishment of global religions, the development of democracy, capitalism, and the scientific method, and the advent of social media; it is still with us today, as recently confirmed by the tribalized Supreme Court.

Scientists are not going to resolve this tension, but they are informing it. Many (probably most) activists on both sides of the abortion issue are driven more by strongly held beliefs than by the logical outcomes of scientific inquiry. Nevertheless, the better information scientists provide over time can help individual women make their decisions with more precise awareness of what they are deciding, and can help governments and healthcare providers at every level make better decisions to minimize the damage done by the reversal of Roe v. Wade: greater availability of sex education, contraception (including morning-after pills), pregnancy testing, medication abortion pills, travel for abortion, and general reproductive health services.

In the background is the accelerating global trend toward lower birthrates and aging populations, which predicts that global population will peak late in this century and begin to decline. Some countries face rapid population decline sooner and are encouraging people to form families and have more children. If some of the monumental resources that have been dedicated to anti-abortion campaigns could be turned to supporting parents with children instead, that might do more to reduce abortions than any amount of rigging the Federal judiciary. I’m skeptical that this will happen on a large scale, but I’m willing to be surprised.