Washington, DC -- Contrary to the belief held by some, vaginal birth does not appear to be associated with incontinence later in life, a new study has found. The study, published in the December issue of Obstetrics & Gynecology, found that incontinence was more strongly related with family history.

An estimated 30-50% of adult women suffer from urinary incontinence, and vaginal delivery is often considered to be the major risk factor for stress urinary incontinence. While 62% of urogynecologists previously surveyed would support performing elective cesarean deliveries to prevent incontinence in the long term, the benefit of this practice has not been proven. Risk factors for incontinence include body mass index, hypertension, and integrity of the pelvic floor, all of which tend to run in families.

Researchers from the University of Rochester Medical Center in New York studied 143 pairs of biological sisters. All of the women were at least 45 years old and postmenopausal. All but two pairs of sisters were Caucasian. However, one sister of each pair was nulliparous (no deliveries) and one was parous (at least one vaginal delivery). The women answered questionnaires and underwent clinical testing to measure incontinence.

The researchers found that the rate of incontinence was 47.6% for nulliparous women and 49.7% for parous women, a statistically insignificant difference. They did discover, however, that 63% of the pairs shared continence status (i.e. either both were continent or both were incontinent). The researchers say that their findings run contrary to the conventional wisdom that nulliparity protects against incontinence and are similar to findings from their earlier study of nuns who had never given birth and yet still had high rates of postmenopausal incontinence.

While further research is needed to determine if there is a genetic component to incontinence, the researchers say that this study indicates that family history is more strongly associated with incontinence than a history of vaginal delivery.

Contact: Gunhilde M. Buchsbaum, MD, University of Rochester Medical Center, Rochester, NY, at gunhilde_buchsbaum@urmc.rochester.edu.

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