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Ideas | Chelsea Conaboy

The abortion debate doesn’t change, but the science of abortion does

Michelle Kondrich for the Boston Globe

As a confirmation fight over another Supreme Court seat looms, the abortion debate in the United States sounds much the same as it always has. In the 45 years since Roe v. Wade affirmed a constitutional right to abortion access, groups on both sides of the heated debate deploy many of the same slogans that appeared on protest signs in 1973.

In the interim, though, scientists have made leaps in understanding human development in its earliest stages. Reproductive technologies that raise some of the same issues as abortion — does life begin at conception? — have become common while generating a fraction of the public controversy. The nature of abortion itself has shifted, from a surgical procedure to one that at least in early pregnancy can be induced with a series of pills. And researchers have systematically answered questions that were unanswerable in 1973: Is legal abortion safe? And how does having an abortion — or being denied one — affect a woman’s life over time?


As the Senate prepares to consider President Trump’s latest nomination to the Supreme Court, and as legal scholars evaluate the various ways that a Justice Brett Kavanaugh could alter abortion access, science has changed the backdrop against which the political and legal drama is playing out.

Four and a half decades of medical advances have exposed the power of information encoded in the DNA of a fertilized egg and hastened the point at which a fetus is viable outside the womb — while also refuting claims that abortion harms women who undergo it and undermining the notion that pregnancy begins in a single moment of conception. These advances don’t relieve judges, lawmakers, and voters of the need to render moral judgment — but they could complicate the calculus.

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In courtrooms and legislative chambers, policy makers often seek to draw clear moral lines — an approach that gives pause to many in the scientific community. Historian and philosopher Jane Maienschein, now director of the Center for Biology and Society at Arizona State University, served as science adviser to US Representative Matt Salmon, an Arizona Republican, in the late 1990s. She was alarmed by how little congressional staffers knew about human development even as they drafted legislation to restrict funding for stem cell research. Soon after Dolly the sheep was born in 1997, marking the first successful cloning of a mammal, Maienschein said she had to explain why imposing a ban on “genetic duplicates” would outlaw identical twins.

The staffers’ knowledge was almost wholly derived from talking points delivered by advocacy groups, said Maienschein, who later started a peer-reviewed online encyclopedia of the embryo. Their understanding of the embryo “was all social,” she said. “There was no biological — there was no understanding of the larger picture.”


That larger biological picture is dramatically different than it was in 1973. Consider that the human genome was finally sequenced in 2003 (mostly, anyway), and today the results of DNA testing kits are deliverable right to your inbox. The American public has developed a kind of reverence for DNA and the idea that a person’s identity is determined when egg meets sperm and unique DNA is formed.

That serves a central belief of anti-abortion-rights advocates: Human life begins with a human genotype, determined at conception, which sets in motion a distinct path of development. “A fetus is the same being that he is going to be as an infant,” said Dr. Ingrid Skop, a physician in San Antonio and a board member of the American Association of Pro-Life Obstetricians and Gynecologists. “He’s the same being he is going to be as a child or an adult. He’s just at a lower stage of development.”

But Justice Harry Blackmun, in writing the majority opinion on Roe, recognized the scientific advancements that were already complicating that linear thinking, including what were then emerging techniques for artificial insemination and the implantation of embryos, the more distant use of artificial wombs, and new research that showed conception occurs over time, not in an instant. “We need not resolve the difficult question of when life begins,” Blackmun wrote. “When those trained in the respective disciplines of medicine, philosophy, and theology are unable to arrive at any consensus, the judiciary, at this point in the development of man’s knowledge, is not in a position to speculate as to the answer.”


That statement was dishonest, said Dr. Donna Harrison, executive director of the antiabortion obstetricians’ group and an associate scholar with the Charlotte Lozier Institute, an antiabortion policy and research group. The idea that we don’t know when life begins, she said, “is baloney.”

“There’s been no revelation since we knew that when sperm and egg fuse you have an embryo, a one-celled embryo called a zygote,” she said. “That has not changed at all.”

Of course an embryo is human. But, abortion-rights advocate say, when does it become an individual, entitled to the same rights that you and I have? When does it become a person? That question has been the subject of public debate and court filings over the past decade or so, driven largely by abortion opponents frustrated by incremental limitations on the procedure.

Ballot measures designating conception as the start of personhood have failed in several states. Alabama voters will consider one in November. But, as a matter of science, there may be no good answer to the question of personhood, says developmental biologist Scott Gilbert.

He writes and speaks often on the topic, echoing Blackmun: Among embryologists, there is no consensus. The argument that life starts with fertilization is a “weak” one, he says. For one thing, it obscures the fact that the same genetic material can go on to develop into not one person but two or three. And in very rare cases, two embryos can combine to form a chimera, creating one human made up of cells that originated in two separate zygotes.


But even in more typical human development, embryologists differ on when they perceive the start of a person, Gilbert says. Some hold that it begins at fertilization. Others put it at 14 days, which is around the point that embryos lose the ability to develop into twins or triplets. That’s also where researchers have drawn an ethical line in the sand, known as “the 14-day rule,” at which in vitro development should be halted, with some countries writing that limit into law. Still other embryologists hold that a fetus doesn’t become a person until it develops human-specific brain activity at about 24 weeks or later, Gilbert says, or even until it takes its first breath.

The notion that DNA determines everything ignores modern epigenetics, the study of traits triggered by how genes are expressed rather than by differences in the underlying genotype. The environment — the bacteria a baby is exposed to as it passes through the vaginal canal, for example, or attentive maternal care — determines the expression of a person’s genes.


“We keep hearing from Ancestry.com and 23andMe that you are who your DNA is,” Gilbert wrote in an e-mail. “But that’s denying that who you are depends on how your parents raised you, who your friends were, what teachers you had, and so forth. It also denies the reality of education and religious faith in a person’s life. Kindness, cruelty, love and caring are not encoded in our DNA.”

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Participants in the March for Life rally on the National Mall in January 2017. The annual event protests the Roe v. Wade decision.Chip Somodevilla/Getty Images

The 1978 birth of Louise Brown, the first “test tube baby,” and the incredible growth of in vitro fertilization since then poses a special kind of problem for those who argue personhood begins at conception. Now a common procedure, in vitro fertilization typically involves creating more embryos than are ever implanted; in allowing them to be donated for research, destroyed, or frozen indefinitely, patients and their doctors are presuming that these embryos fall somewhere short of full personhood. Yet far fewer Americans see those procedures as morally wrong than hold that view of abortion, according to a 2013 survey by the Pew Research Center.

Still, anti-abortion activists in recent years have asked the courts to determine the fate of preserved embryos when the partners who created them are in dispute, and to do so under state child-custody statutes or to consider the embryos’ unalienable right to life.

Asking the court to recognize an embryo as a person rather than seeking such a definition from lawmakers or from the voting public is “strategically savvy,” Harvard Law professor I. Glenn Cohen and Dr. Eli Y. Adashi, an ob-gyn and a professor of medical science at Brown University, wrote in the New England Journal of Medicine in June. Anti-abortion advocates have succeeded in restricting abortion at the state level, but “the movement has largely failed to sway public opinion regarding restrictions on reproductive technologies,” they write. “This resistance is unsurprising, given that many voters may be friends, siblings, parents, or grandparents of children conceived using these technologies, whereas abortions remain shrouded in secrecy.”

In fact, a third of American adults say they have had some kind of fertility treatment or know someone who has, a recent survey by the Pew Research Center found.

Abortion opponents cite two ways they see scientific advancements serving them in the court of public opinion. First, improvements in health care have increased the chance of survival among infants born well before term. Roe v. Wade set viability as the threshold before which states could not prohibit abortion, and the 1992 Planned Parenthood v. Casey ruling affirmed that limit. Blackmun did not define viability but said it can occur around 24 weeks and is more typical around 28 weeks.

Today, the consensus among neonatologists is that infants born at or before 21 weeks will not survive and that most born after 24 weeks will survive if given necessary care to help them breathe and to maintain a healthy heart rate and body temperature. The period between is less certain. Echoing other studies, a large study conducted at 11 academic medical centers in the United States found that rates of survival for infants born at 23 and 24 weeks increased between 2000 and 2011. Outcomes for survivors improved as well, with those born in the later part of the study period being less likely to suffer neurodevelopmental impairment as toddlers.

Better standards of care in neonatal intensive care units — improved hand washing to avoid infection, for example, and more support for women providing breast milk for their babies — account for much of the change, said Dr. Michael Cotten, a study author and chief of neonatology at Duke University School of Medicine. He and co-author Dr. Noelle Younge said they know that their group’s research is used by advocates as a talking point in the abortion debate, but their mission is to provide more information to parents facing that window of uncertainty. “It’s just not that simple to determine viability,” Younge said. “It really is an individual, case by case determination.”

For Skop, the board member in the antiabortion obstetricians’ group, improvements in preterm survival underline that the viability line is an arbitrary one. She thinks the general public sees that, too. “Where is a good line to draw?” she said. “There really isn’t a good line to draw, unless you are going to draw it either very low, at the beginning of the existence of the human being, or unless you are going to draw it at birth.”

The ubiquity of ultrasound images is the second post-Roe development that abortion opponents point to. As sonograms became common in the United States in the 1980s, the idea of a fetus as just a clump of tissue — “that didn’t really wash anymore, when everybody could see for themselves,” said Randall O’Bannon, director of education and research for National Right to Life.

Today, expectant parents often announce their pregnancy by posting ultrasound snapshots on social media. Meanwhile, the technology has become a tool to restrict abortion. Though they are not considered medically necessary during first-trimester abortions, 14 states mandate that an abortion provider perform an ultrasound first, and three of those states require that the provider show and describe the image to the patient.

O’Bannon believes the proliferation of ultrasound images have helped reduce annual abortions in the United States. Among women ages 15 to 44, the abortion rate dropped from 19.4 per 1,000 in 2008 to 14.6 in 2014. Researchers at the Guttmacher Institute, a research and policy institute focused on reproductive rights, attribute the decline primarily to improved contraceptive use and a decrease in unwanted pregnancies.

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A protester in January shows support for the 1973 case upholding a woman’s right to have an abortion.AP Photo/Rich Pedroncelli

The same analysis concluded that nearly 1 in 4 women will have an abortion by age 45. Abortion is common in the United States, and it’s more openly discussed than it was before Roe. “Women don’t see it as such a dramatic event as they may have seen it in the ’70s,” said Dr. Ana Langer, director of the Women and Health Initiative at the Harvard T. H. Chan School of Public Health.

Robust research on the safety of abortion may account for some of that shift. Abortion opponents have long argued that the procedure is harmful to the physical or mental well-being of women who undergo it. In March the National Academies of Sciences, Engineering and Medicine published a report reviewing studies that evaluate the risks and long-term effects of abortion procedures. Its authors concluded that legal abortion today is “safe and effective,” and that most abortions can be performed safely in an office or clinic settings.

In one landmark study, reproductive health researchers at the University of California, San Francisco, interviewed hundreds of women who sought abortions at 30 abortion facilities across the country. They compared those who obtained an abortion to those who were turned away because they had just passed the facility’s gestational limit for the procedure. Most of the latter group went on to give birth.

Researchers followed the women for five years and found that having an abortion did not increase a woman’s risk of becoming depressed or developing post-traumatic stress disorder. In fact, those who were denied an abortion were at greater risk of anxiety symptoms and low self-esteem in the short term and were far more likely to see their household incomes fall below the poverty level. Among women who had an abortion, 95 percent said during interviews in the three years following the abortion that they made the right decision.

Diana Greene Foster, principal investigator of what’s known as the Turnaway Study, said the work of her group and others have made the argument that abortion hurts women nearly indefensible. “I’m sure there are people who still believe it,” she said, “but as a political argument, I think it’s losing credibility.”

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Even so, there are limits on policymakers’ willingness to suspend moral judgment, and efforts by scientists to make abortion safer and simpler have met with stiff resistance. Many abortion-rights advocates thought that obtaining an abortion in the 21st century would become as easy as visiting the doctor’s office. The US Food and Drug Administration in 2000 approved the drug mifepristone, developed in the 1980s in France and typically taken with a second drug, misoprostol, to induce abortion.

“The hope that we all had in the early 2000s was that this very simple regimen would make abortion far more accessible,” said Susan Yanow of Cambridge, co-founder of Women Help Women, which mails abortion pills to women around the world, though not in the United States. “That has not come to fruition.”

Despite mifepristone’s proven safety, the FDA has maintained restrictions on its use. In the United States, the drug may be dispensed only in a clinical setting — not by prescription from a pharmacy — and by a provider who has obtained a special certification from the drug distributor, something few doctors were willing to do if they weren’t already known as abortion providers.

Still, even as the number of abortions performed in the United States each year has shrunk, use of medication abortion has grown dramatically. Of the abortions within the first nine weeks of gestation in 2014, an estimated 45 percent were medication abortions. That figure is expected to grow with a trend toward earlier abortions and as women become more familiar with the option.

Some advocates say the medications, if made much more accessible, could fill a gap in the continuum of fertility management options between Plan B emergency contraception and a clinic-based abortion procedure — a kind of backup plan for a missed period. Researchers are now testing the feasibility of sending abortion pills through the mail to patients who consult with a doctor via telemedicine, and illegal online pharmacies provide easy access to the pills for women looking to manage their own abortion.

Abortion pills have changed DIY abortion, said Dr. Daniel Grossman, professor of obstetrics, gynecology, and reproductive sciences at the University of California, San Francisco. Before Roe, a self-managed abortion “might have been coat hangers and other invasive things that were put inside the uterus,” he said. “Now, it’s two pills. Regardless of what happens to the abortion law in the US, I think women will find ways to get access to these medications to have an abortion on their own.”

Perhaps for that very reason, abortion pills are likely to be a focus in state legislatures and courthouses for years to come. In Arkansas, for example, women seeking an abortion already must receive counseling and wait 48 hours. Abortion by telemedicine and most abortions after 20 weeks gestation are banned. Now the state could become the first to effectively block use of medication abortion by requiring doctors who administer the pills to contract with a physician who has hospital admitting privileges. The Supreme Court in May refused to hear a challenge to the 2015 law, though a federal appeals court in August upheld a temporary injunction barring it from taking effect.

Even as science has advanced, the legal framework around abortion has further fractured, leaving a patchwork of abortion restrictions across the United States, including some that clearly counter scientific evidence. Maienschein, the Arizona historian and philosopher focused on the embryo, thinks that’s problematic, and not because she would like to see all restrictions eliminated. In fact, Maienschein says she sees reasonable social and scientific justifications for limiting abortions after 20 weeks gestation.

It’s problematic, she said, because it’s a reflection of Americans’ inability to understand the science and to agree on what it means. Instead, we fall back on political assumptions. “It’s not that the science should — or even could — tell us what to do in policy,” she said. “But it can — and should — inform that policy.”

Chelsea Conaboy is a writer and editor focused on health care. Read more of her work at chelseaconaboy.com.