NEW YORK (Reuters Health) - Women who have never experienced childbirth are just as likely as those who have given birth to develop urinary incontinence, a finding that casts doubts on the theory that vaginal deliveries increase the risk of incontinence, US researchers report.

In a survey of nuns who had never given birth, half said they had urinary incontinence, according to Dr. Gunhilde M. Buchsbaum and her colleagues at the University of Rochester in New York. This is a rate roughly equivalent to that seen in women who have experienced vaginal birth.

These findings contradict the theory that women who give birth vaginally undergo anatomical stress during delivery that places them at risk of urinary incontinence. Indeed, Dr. Buchsbaum told Reuters Health that some mothers have requested to undergo cesarean section to reduce their risk of developing incontinence.

"What we found was pretty much against common belief," Dr. Buchsbaum said.

The authors base their findings on surveys of 149 nuns, who were an average of 68 years old. The nuns provided information about whether they had experienced incontinence, and the impact the condition had on their lives.

Dr. Buchsbaum's team found that 30% of the nuns experienced stress incontinence and 24% had symptoms of urge incontinence. Some of the nuns also had incontinence that appeared related to both stress and urgency, while others had incontinence that was not related to either type.

Nuns who were depressed, had a history of urinary tract infections (UTI), and a relatively high body mass index were more likely than others to also be incontinent, according to the report in the August issue of Obstetrics & Gynecology.

In an interview with Reuters Health, Dr. Buchsbaum speculated that the theory that vaginal birth increased the risk of incontinence stems from the fact that so many women have given birth. Consequently, more incontinent women have given birth than haven't, which may have led researchers to suspect that childbirth played a role in the condition.

Why urinary incontinence was linked to depression, multiple UTIs and weight, remains unclear, the researcher said, although these findings support previous reports.

Many of the nuns in this study experienced a profound effect of their incontinence on their lives, Dr. Buchsbaum added, and about half of those who reported incontinence used sanitary pads to protect themselves from urine leaks. In addition, some reported being unable to sleep through the night, go on long trips or even go to church.

This study does not totally discredit the theory that vaginal delivery plays a role in incontinence, Dr. Buchsbaum noted. As such, she and her colleagues are conducting another study to compare women who have never given birth to their sisters who have delivered at least one infant vaginally to see if there is a genetic predisposition to becoming incontinent.

Regardless, these findings "seriously put into question that childbirth is the major factor for the development of urinary incontinence," Dr. Buchsbaum noted.

Obstetr & Gynecol 2002;100:226-229.

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