Overall, about 60 to 70 percent of the women had longer feet and shorter arches after childbirth, the researchers said. Eleven of the women reported changes in their shoe size, the researchers said.

While previous studies have documented changes in foot size during pregnancy, none had looked to see if the changes persisted after delivery. “I heard so many women talking about having to go buy new shoes after pregnancy,” said study researcher Neil Segal, an associate professor of orthopaedics and rehabilitation at the University of Iowa. This prompted Segal to look into the issue further.