Many states have laws that require a waiting period before an abortion, or an ultrasound. If the U.S. Supreme Court overturns its 1973 Roe v. Wade decision that legalized abortion, women will face even more hurdles in some parts of the country, and may have to travel to another state get an abortion.

That means more women could end up having the procedure later than they wish.

“It’s not because people don’t want to have them sooner,” said Dr. Diane Horvath, an OB-GYN in Baltimore, Maryland, who has performed abortions for 16 years. “It’s because barriers and new information cause them to have to push it back to later in pregnancy.”

Nearly 93% of legal abortions performed in the U.S. in 2019, the most recent data available, occurred within the first 13 weeks of pregnancy, or in the first trimester, according to the Centers for Disease Control and Prevention. Just over 6% were performed at 14 to 20 weeks’ gestation, and even fewer, less than 1%, were performed at 21 weeks or later, in the third trimester.