Pregnancy may increase a woman's foot size, a change that appears to be permanent, according to a new study.
Researchers measured the arch height and foot length of 49 women during their pregnancy and five months after they had given birth. On average, the women's arch height decreased, and in turn, their foot length increased between 2 and 10 millimeters (about 0.1 to 0.4 inches) -- during this period.
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.
In an earlier study, Segal surveyed about 110 women at a mall, and asked if their shoe size had ever changed during their adult years. While just 13 percent of women who'd never been pregnant said it had, between 30 to 60 percent of women who had been pregnant at least once said their shoe size had changed.