The constitutional right to an abortion has been struck down in the United States. The US Supreme Court announced on June 24 that it would overturn the 1973 landmark decision Roe v. Wade, which had protected abortion access up until the point that a foetus can live outside the womb — typically set at 22 or 24 weeks of pregnancy.

Public-health researchers have renewed their warnings about the harms that this decision will bring to the country.

The outcome is not a surprise to them, because an initial draft opinion was leaked to news outlet Politico in May. “All I could add at this point is how disappointing it is to see that the majority opinion, like the leaked draft, ignores the fact that there is solid scientific evidence that this decision will harm women,” says Caitlin Myers, an economist at Middlebury College in Vermont, who has studied the financial impacts of abortion restriction.

The high court issued its decision with regard to the case Dobbs v. Jackson Women’s Health Organization, in which the only clinic in Mississippi that provides abortions challenged a 2018 state law banning most abortions after 15 weeks of pregnancy. The law, the clinic argued, stood in direct opposition to Roe.

The six-against-three ruling, authored by conservative Justice Samuel Alito, states that: “Roe was egregiously wrong from the start. Its reasoning was exceptionally weak and the decision has had damaging consequences.”

With Roe v. Wade overturned, abortion rights will now be left to individual US states to decide. Twenty-six states are certain or likely to ban abortion, according to the Guttmacher Institute, a research organisation that supports abortion rights. Of those, 13 have ‘trigger bans’ in place — laws that will take effect either immediately or by quick state action.

Public-health researchers and economists submitted evidence to the Supreme Court ahead of the case showing that restricting abortion access has negative consequences for pregnant people, who are at increased risk of physical and mental-health issues when they are denied an abortion, and for infant health.

“We know from other severe restrictions in states like Texas what happens when abortion access is curtailed,” says Liza Fuentes, a senior research scientist at the Guttmacher Institute, based in New York City.

In 2013, when Texas passed legislation including a ban on most abortion procedures after 20 weeks of pregnancy, the state’s abortion rate dropped by 13 per cent. Scaled up, that represents more than 100,000 people in the United States being denied an abortion post-Roe and having the potential for negative outcomes, Fuentes says. “And that’s a pretty conservative estimate.”

A substantial proportion of people who want abortion services but don’t have access to them will end up carrying their pregnancies to term. The consequences of this have been documented thoroughly by research. One of the most comprehensive studies examining the effects of abortion access is the Turnaway Study, an effort that followed about 1,000 US women for five years after they sought abortions and either received or were denied them.

Led by Diana Greene Foster, a reproductive-health researcher at the University of California, San Francisco, the study showed, for example, that women denied an abortion were more likely to live in poverty afterwards than those who received one. And it showed that those denied an abortion were more likely to report not having enough money to cover living expenses over the five years than were those who did not give birth. Women who were unable to receive the procedure also fared worse in areas such as education and physical and mental health.

Once people who are denied an abortion go through the experience of giving birth, they rarely choose to place the child for adoption, the Turnaway Study showed.

“It means that poor families will have kids before they’re ready,” Greene Foster says. “And all the health and economic costs that we documented in the Turnaway Study will happen for these people.” She is currently working on a new national study to investigate what will happen to the people denied an abortion after their states’ laws change abruptly post-Roe.

Mary Faith Marshall, a biomedical ethicist at the University of Virginia School of Medicine in Charlottesville, says that, on the basis of data collected over years, the upcoming abortion restrictions will have their deepest impacts on people of colour and poor communities. “Being forced to have a child when it is not the right time puts people who are already in poverty further into poverty.”

One of the most immediate consequences of Roe’s demise is that many people seeking an abortion will now need to travel significant distances to receive care. Myers has estimated that, within a few months of Roe being overturned, 54 per cent of US women seeking abortions will have to travel farther than they would have previously to reach their nearest abortion provider.

For these women, travel distance will increase from about 58 kilometres (36 miles) on average to about 441 kilometres (274 miles) on average. These numbers haven’t been published yet, but they closely follow results that Myers and her colleagues published in the journal Contraception in 20193.

“Based on what we know about how women respond to travel distance, about three-quarters of them are still going to manage to get out and reach a provider, and about a quarter of them won’t,” Myers says. This quarter represents the poorest and most vulnerable people, she adds.

Overturning Roe will also affect the states where abortion remains legal. “What’s going to happen in the immediate aftermath is there’s going to be an enormous outflow of hundreds of thousands of women from the states that ban to the states where abortion is still legal,” Myers says. “My belief is those providers are not currently prepared to fully absorb that huge increase in demand.”

Another potential consequence of restricting access to abortion is that people might try to end their pregnancies without clinical supervision. Some are likely to do this with abortion medications, which are safe and effective, according to the World Health Organization.

The problem is that many people don’t know much about abortion medication, says Heidi Moseson, an epidemiologist based in Oakland, California, who works at Ibis Reproductive Health, a global research organization that supports abortion rights. She and her colleagues have studied abortion attempts among transgender, non-binary and gender-expansive people in the United States. One in five people in their study who had ever been pregnant tried to self-manage an abortion. “Unfortunately, no one reported using medication abortion,” Moseson says. “They reported things like physical trauma, inserting objects into the vagina and ingesting substances that are harmful.”

To bridge that information gap, Ibis and partner organisations developed an app, called Euki, that provides people with information on sexual and reproductive health, including how to have an abortion using medication. What can be more difficult to deal with, Moseson says, are the legal risks of obtaining abortion pills in the United States.

“People have been prosecuted for self-managing their abortion, and some laws have been applied outside of their intended scope to criminalise people,” Moseson says.

Marshall notes that the consequences of overturning Roe will fall on all pregnant people, not only on those seeking an abortion. In a June article in The American Journal of Bioethics5, she and her co-authors highlighted that people with pregnancy complications or adverse pregnancy outcomes such as miscarriages or stillbirths might become vulnerable to legal surveillance and criminal prosecution.

“Roe cemented that pregnant people had constitutional rights,” Marshall says. “Now, they will no longer have these legal protections and will not be full persons under the US Constitution, which I think is a travesty.”

• A Nature report