Association between vaginal parity and rectocele.

Introduction And Hypothesis: Rectocele is common in parous women but also seen in nulliparae. This study was designed to investigate the association between vaginal parity and descent of the rectal ampulla/rectocele depth as determined by translabial ultrasound (TLUS).

Methods: This retrospective observational study involved 1296 women seen in a urogynaecological centre. All had undergone an interview, clinical examination and 4D ultrasound (US) imaging supine and after voiding. Offline analysis of volume data was undertaken blinded against other data. Rectal ampulla position and rectocele depth were measured on Valsalva. A pocket depth of 10 mm was used as a cutoff to define rectocele on imaging.

Results: Most women presented with prolapse (53%, n = 686); 810 (63%) complained of obstructed defecation (OD). Clinically, 53% (n = 690) had posterior-compartment prolapse with a mean Bp of -1 [standard deviation (SD)1.5; -3 to 9 cm]. Mean descent of the rectal ampulla was 10 mm below the symphysis (SD 15.8; -50 to 41). A rectocele on imaging was found in 48% (n = 618). On univariate analysis, OD symptoms were strongly associated with rectal descent, rectocele depth and rectocele on imaging (all P < 0.001). The prevalence of a rectocele seen on imaging increased with vaginal parity (P < 0.001). One-way analysis of variance (ANOVA) of vaginal parity against rectal descent and rectocele depth showed a dose-response relationship (both P < 0.001).

Conclusions: Vaginal parity was strongly associated with descent of the rectal ampulla and rectocele depth. This relationship approximated dose-response characteristics, with the greatest effect due to the first vaginal delivery.