By Rita Rubin
Gannett News Service

Having a C-section instead of a vaginal delivery may protect against urinary incontinence early on, but the advantage fades by middle age, says a new study.

Fear of incontinence is one reason some pregnant women schedule an elective C-section, even though they could deliver vaginally. Childbearing is known to be a risk factor for urinary incontinence in young and middle-aged women, but it has been unclear whether vaginal delivery or pregnancy itself is to blame, Norwegian researchers write in the New England Journal of Medicine.

Previous studies may have been too small to provide conclusive answers, the researchers say. They based their findings on 15,307 Norwegian women enrolled in an ongoing study of incontinence. The women were younger than 65 and had had C-sections only, vaginal deliveries only or no deliveries.

Overall, the researchers found that 10 percent of women who had never had a delivery reported experiencing incontinence, compared with 16 percent of those who had had C-sections and 21 percent of those who had delivered vaginally.

However, says lead author Guri Rortveit of the University of Bergen, "the benefit of C-sections is relatively short-lived." By age 50, when urinary incontinence becomes more common, women who'd had a C-section and women who'd delivered vaginally had similar rates, the researchers found. "I think important new knowledge from our study is that pregnancy is a risk factor of incontinence in itself," Rortveit says.

Potential protection of the pelvic floor is the most important long-term maternal benefit of C-sections, according to the authors of a "sounding board" piece about elective C-sections in the same issue as Rortveit's study.

In 1985, the New England Journal of Medicine published an article advocating elective C-sections, but it had little impact on obstetrical practice at the time, which was focused on halting a rise in C-section rates, the authors write. Today, though, when nearly one in four U.S. deliveries is by C-section, "elective Caesarean delivery is no longer a marginal idea," they say.

Most studies support the idea that women who have a C-section are less likely than women who deliver vaginally to experience incontinence of urine and stool as well as pelvic-organ prolapse, in which the uterus or the vagina has dropped from its normal position, the sounding-board authors write. However, they note, the risk of maternal death, albeit increasingly rare, is estimated to be several times higher with a C-section.