No correlation between perineal position and pudendal nerve terminal motor latency in healthy perimenopausal women

BACKGROUND: Significant associations between perineal descent and pudendal nerve latency have previously been described in fecally incontinent patients. This has led to the hypothesis that pelvic floor muscle and nerve injury initiated by childbirth might progress and cause fecal incontinence. PURPOSE: The study contained herein was undertaken to test whether changes in perineal position and pudendal nerve latency were associated in a population of healthy middle-aged women. METHODS: A cross-sectional study of 144 women were selected randomly from the Danish National Register; they had a mean age of 50 (range, 45-57) years and a mean parity of 2 (range, 0-6). Perineal position at rest and during simulated defecation and pudendal nerve terminal motor latency were measured. All examinations were performed by one of the authors (AMR) and without the knowledge of parity. RESULTS: The perineal position both at rest and during straining was significantly lowered, and the pudendal nerve terminal motor latency was significantly prolonged with increasing numbers of vaginal deliveries (data not shown). There was, however, no association between pudendal nerve terminal motor latency and perineal position at rest (correlation coefficient, r = -0.15, P = 0.1) or during simulated defecation (r = -0.08, P = 0.4). CONCLUSION: Small but significant effects of vaginal deliveries were detected in a random population of healthy perimenopausal women. However, because perineal descent and pudendal nerve latency were not associated, our findings do not support the hypothesis that damage induced by vaginal delivery to the pudendal nerves and pelvic floor will progress.