Stress incontinence and pelvic floor neurophysiology 15 years after the first delivery

Headline This is a longitudinal study of a cohort of primigravidae recruited between 1985 and 1987 and followed up 7 and 15 years later. Pelvic floor neurophysiology was performed and questionnaires were administered to determine the natural history of stress incontinence and to establish whether pelvic floor denervation after the first delivery is associated with symptoms of stress urinary incontinence in the future. Objectives To study the natural history of stress urinary incontinence arising during the first pregnancy, to determine whether postnatal pelvic floor denervation progresses with time and whether it predisposes to stress urinary incontinence in the future. Design Prospective longitudinal cohort study. Setting Tertiary referral urogynaecology unit. Sample Cohort of 96 primigravidae studied prospectively between 1985 and 1987 and followed up 7 years (n = 76) and 15 years (n = 55) later. Methods Urinary incontinence symptoms were recorded and pelvic floor neurophysiology was performed antenatally and postnatally between 1985 and 1987. Repeat neurophysiological tests and questionnaires were completed by those relocated 7 and 15 years later. Main outcome measure Symptoms of stress urinary incontinence. Secondary outcomes Symptoms of urge urinary incontinence and anal incontinence; motor unit potential duration and pudendal nerve terminal latency; vaginal squeeze pressure measured by perineometry. Results Prevalence of stress incontinence was highest during pregnancy and had increased seven years after the first postnatal period (P = 0.0129). Two-thirds of women with antenatal stress incontinence had stress incontinence 15 years later. One-third of women with stress incontinence at any time appear to undergo resolution of symptoms. Motor unit potential duration increased at seven years (P = 0.036). Vaginal squeeze pressure improved during the same period (P = 0.0007). Conclusions When stress urinary incontinence arises during the first pregnancy, the risk of stress incontinence occurring 15 years later is doubled. Although pelvic floor reinnervation progressed after the postnatal period, the absence of an adequate marker for pelvic floor denervation makes it of uncertain clinical significance.