Ruptures to the anal sphincter during childbirth can cause long-term incontinence, pain and other problems for many women, so serious tears are usually surgically repaired, often immediately after delivery.
However, a surgeon with expertise in the repair is not always immediately available.
To see whether delaying the procedure affects women's long-term recovery, Swedish researchers randomly assigned 165 women with anal sphincter tears to receive surgery either right after delivery or eight to 12 hours later.
Over the next year, there were no significant differences in incontinence symptoms between the two groups, the researchers report in the obstetrics journal BJOG.
By the one-year mark, most women in both surgery groups said they "never" had fecal incontinence, report Dr. J. Nordenstam and colleagues at the Karolinska Institute in Stockholm.
Gas incontinence was a continuing problem for about half of the women in each group.
The findings, according to Nordenstam's team, suggest that "there is no benefit or harm" from delaying repair of anal sphincter tears for up to 12 hours.
Surgery should not routinely be delayed, the researchers say, but in cases where an experienced surgeon is not readily available, women can wait to have the procedure.