Women who have Caesarean sections rather than vaginal deliveries run a significantly lower risk of incontinence later in life, a study found.

The difference alone is not reason enough to opt for a C-section, the researchers cautioned.

``The prevention method here is so drastic _ it's surgery with medical and economic costs,'' said Dr. Guri Rortveit of the University of Bergen in Norway.

Vaginal birth has long been considered a cause of urinary incontinence because of damage to muscles and nerves during labor and delivery. The role of a Caesarean birth was less clear.

In the study of 15,307 Norwegian women, the researchers found that about 21 percent of those who had vaginal deliveries were incontinent, compared with about 16 percent of those who had Caesareans. The rate was 10 percent for childless women.

Moderate or severe leakage of urine was twice as likely after vaginal delivery than after C-section, according to the findings, reported in Thursday's New England Journal of Medicine.

The risk of incontinence is just one factor women contemplating an elective Caesarean should consider, said Dr. Howard Minkoff of New York's Maimonides Medical Center. Minkoff is the co-author of another article in the journal that reviews the pros and cons of an elective Caesarean and encourages doctors to discuss them with patients who ask.

``There is clearly evidence of increasing benefit _this is one of them _ and there's clearly decreasing evidence of risks. That said, I don't think the scales have tilted dramatically,'' said Minkoff, who still favors normal delivery.

Dr. Laura Riley, an obstetrician at Massachusetts General Hospital, said she would discourage patients from having a Caesarean to prevent incontinence because of the risks of bleeding, infections and other complications from the surgical procedure.

``There are some worse risks of Caesarean delivery than incontinence,'' she said.

The Norwegian study included women ages 20 to 65 who lived in the county of Nord-Trondelag. They answered questions about the frequency and amount of leakage; birth records and the type of delivery were obtained from a national birth registry.

The study did not include women who had delivered by both methods.

The findings show the rate of incontinence increased with age, weight, the number of years since last delivery and, for vaginal delivery, with the number of deliveries. An earlier study by the researchers showed childbirth had no effect on the rate of incontinence after age 65.

Most incontinence can be successfully treated with such things as exercise, bladder training and medication, and surgery is an option for serious cases, Rortveit said.

She said the findings should be valid for other Western women despite differences in the rate of Caesareans. In the United States, 24 percent of births are by Caesarean, while the rate in Norway is nearly 13 percent.

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