The almost certain confirmation of Amy Coney Barrett to the Supreme Court has increased the chances that Roe v. Wade will be weakened or overturned. If that were to happen, abortion access would decline in large regions of the country, a new data analysis shows.

Legal abortion access would be unchanged in more than half of states, but it would effectively end for those living in much of the American South and Midwest, especially those who are poor, according to the analysis.

“A post-Roe United States isn’t one in which abortion isn’t legal at all,” said Caitlin Knowles Myers, an economist at Middlebury College and a co-author of the original research. “It’s one in which there’s tremendous inequality in abortion access.”

Today, there is at least one abortion clinic in every state, and most women of childbearing age live within an hour’s drive or so of one, the analysis found. Without Roe, abortion would probably become illegal in 22 states. Forty-one percent of women of childbearing age would see the nearest abortion clinic close, and the average distance they would have to travel to reach one would be 280 miles, up from 36 miles now.

As distances to clinics increase, abortion rates decline, research shows. Women who can’t afford to travel to a legal clinic or arrange child care or leave from work for the trip are most affected. Also, remaining clinics would not necessarily be able to handle increased demand.

Without Roe, the number of legal abortions in the United States would be at least 14% lower, Myers and her colleagues estimated. That could mean about 100,000 fewer legal abortions a year, they found. The number is impossible to predict precisely because new clinics could open on state borders, and some people may order abortion pills by mail or obtain illegal surgical abortions.

The estimates are based on two elements: research of how recent clinic closings in Texas affected abortion rates among women whose driving distance to providers increased, and two sets of assumptions about which states might outlaw abortion if Roe were overturned.

That research was published last year in the journal Contraception by Myers; Rachel Jones, a sociologist at the Guttmacher Institute, a research group that supports reproductive rights; and Ushma Upadhyay, an associate professor at the University of California, San Francisco.