Legal abortions most likely increased in the United States in the first six months of the year compared with 2020, an analysis of new estimates shows, as states with more permissive abortion laws absorbed patients traveling from those with bans and access to abortion pills via telemedicine continued to expand.

New research from the Guttmacher Institute offers the latest view of legal abortions since the Supreme Court’s Dobbs decision last year upended access to abortion nationwide and allowed more than a dozen states to ban or restrict the procedure.

The data suggests that thousands of women have crossed state lines to obtain an abortion, in the face of restrictions at home. It also indicates a rise in abortions among those living in states where the procedure is legal.

“You have two forces at work,” said Caitlin Myers, an economist at Middlebury College, who reviewed the Guttmacher report. “On the one hand, you have people trapped in ban states, and, on the other, you have people in a whole lot of the country where access has improved.”

Altogether, about 511,000 abortions were estimated to have occurred in areas where the procedure was legal in the first six months of 2023, a review of Guttmacher’s data shows, compared with about 465,000 abortions nationwide in a six-month period of 2020.

Abortions rose in nearly every state where the procedure remains legal, but the change was most visible in states bordering those with total abortion bans. Many of these states loosened abortion laws, and providers opened new clinics to serve patients coming from elsewhere. In Illinois, for example, where abortion is legal, abortions rose an estimated 69 percent in 2023 compared with the same period in 2020, to about 45,000 from 26,000.

Other states with restrictive neighbors, like Colorado, Kansas, New Mexico and South Carolina, also had jumps in estimated counts of abortions.

Arizona, Georgia and Indiana, by contrast, sought to restrict abortion, and all three states had drops in their estimates. Arizona and Georgia have gestational limits on the procedure, and Indiana recently enacted a total ban.

Researchers emphasized that the rise in abortions so far in 2023 does not mean that state bans have had no impact on access.

“Travel doesn’t come without a cost,” said Isaac Maddow-Zimet, a data scientist at the Guttmacher Institute and the lead researcher on the institute’s report. “Just because someone isn’t denied an abortion doesn’t mean it was an easy experience. And we know that some can’t leave their state.”

There are no estimates yet of women who were denied abortions or those who were unable to get them. The increases in most states may also mask the number of abortions prevented by the bans.

“Abortions had begun rising in advance of Dobbs, and they may have continued to rise even more steeply than observed if it weren’t for the bans,” Dr. Myers said.

The Guttmacher Institute’s report is based on a survey of physical abortion clinics and telehealth and virtual providers. The institute, which supports abortion rights, does not contact all clinics in each state but relies on a sample to estimate the number of abortions.

The report excludes abortions obtained outside of the formal health care system, through, for example, pills mailed into states with bans from other countries or states where abortion is legal. Other data suggests that thousands of people, especially those living in states with bans, have ordered abortion pills online from overseas.

Populous states like California, Florida, Illinois and New York had the most abortions. Because the researchers relied on a statistical model, they reported a range of uncertainty in their counts, and there was more uncertainty in states with more abortion providers. Data was not collected from the 14 states with abortion bans in effect in the first part of the year.

Researchers compared this year’s data with 2020, the most recent year of their annual provider survey and the last year before major abortion restrictions took effect. (Texas passed a six-week abortion ban in 2021, before the Dobbs decision.) Abortions were already rising that year, reversing a decades-long decline.

The data may also capture effects of other policy shifts in recent years, including the Biden administration’s decision during the pandemic to allow abortions via telemedicine, as well as other unknown impacts of the pandemic.

The state-level monthly estimates are in line with abortion statistics from January through March of this year released by WeCount, another group that surveys providers.

Both reports show significant increases in abortions in states without abortion bans, a change that anti-abortion advocates and legislators are watching closely.

“There is the feeling among legislators that we’ve passed strong laws here and yet our neighbors in Colorado or Illinois are allowing these businesses to pop up on our border,” said Katie Daniel, the state policy director at Susan B. Anthony Pro-Life America.

Researchers caution that more work is needed to better assess both the impact of abortion restrictions as well as the explosion of access to abortion pills through telehealth and underground networks.

The picture is expected to shift later this year, as more restrictions take effect. Guttmacher researchers collected abortion data before legislatures enacted bans and restrictions in Indiana, North Carolina and South Carolina.