Repeated deliveries might disturb the levator function and increase defecation disorders. In this prospective study, we determined the electric activity of the levator ani muscle (LAM) in nullipara, multipara, grand multipara, and great grand multipara (20 subjects for each group). Multiparity, grand multiparity, and great grand multiparity were defined as women having 2 - 5, 6 - 9, and 10 and over deliveries, respectively. The number of deliveries of multipara, grand multipara and great grand multipara were 4.05 ± 1.14 (2 - 5), 7.55 ± 1.23 (6 - 9) and 12.2 ± 2.16 (10 - 17), respectively. All women were asked whether they had experienced constipation, fecal or urinary incontinence, and/or pelvic pain. All women were also evaluated for pelvic organ prolapse. Electromyography (EMG) of the LAM at rest and on contraction was recorded. EMG is an electrical recording of muscle activity. Constipation, incontinence and pelvic organ prolapse were encountered in multipara, grandmultipara and great grand multipara women. The LAM EMG at rest and on contraction in the nullipara was accepted as control. Both the resting and contractile activities of the LAM were as follows: nullipara > multipara > grand multipara > great grand multipara. These findings indicate that levator dysfunction and defecation disorders are increased with repeated deliveries because of pudendal and/or levator ani nerve injury and traumatic injury to the LAM occurred with the mechanical stresses of vaginal deliveries.
2006 Tohoku University Medical Press