Relation between vaginal birth and pelvic organ prolapse.

Objective. To evaluate the relation between vaginal birth and pelvic organ prolapse quantification (POPQ) stages III and IV prolapse and whether each additional vaginal birth is associated with an increase in pelvic support defects. Design. Prospective cross-sectional study. Setting. Gynecology clinic in a University Hospital. Population: Four hundred and fifty-eight nulliparas and 892 multiparas, including 272 with one, 299 with two and 321 with at least three term vaginal deliveries. Methods. In a Human Investigation Committee approved-study, the pelvic support of nulliparas and multiparas who only had term vaginal deliveries was evaluated for prolapse using the POPQ system. Main outcome measure. 1. Difference in POPQ stages III and IV prolapse between nulliparas and multiparas. 2. Difference in POPQ stage distribution among nulliparas and multiparas who had one, two, and at least three term vaginal deliveries. Results. Compared with nulliparas, the odds ratios of having POPQ stage II defect and stage III or IV prolapse associated with multiparas was 2.95 (95% CI: 2.06-4.24) and 1.01 (95% CI: 0.40-2.79), respectively. The prevalence of POPQ stage II defect among nulliparas and multiparas that had one, two, and at least three term vaginal deliveries was 25% (119/458), 50% (137/272), 66% (198/299), and 69% (220/321), respectively (p<0.001), while 1% (6/458), 1% (4/272), 2% (7/299), and 2% (8/321), respectively, had POPQ stage III or IV prolapse (p=0.618). Conclusions. Vaginal birth is not associated with POPQ stages III and IV prolapse, but it is associated with an increase in POPQ stage II defect. [ABSTRACT FROM AUTHOR]