Transperineal ultrasound to estimate the appropriate ring pessary size for women with pelvic organ prolapse

Introduction and hypothesis: The objective was to predict the successful ring pessary size based on the levator hiatal area (HA). Methods: This is a prospective case–control study. Women with symptomatic pelvic organ prolapse (POP) choosing pessary treatment were included. All women underwent an interview, clinical examination, and 3D/4D transperineal ultrasound (TPUS). The ring pessary size used in each trial and the reason for unsuccessful trials were recorded. In addition, levator hiatal area divided by ring pessary size (HARP ratio) was measured at rest, maximum contraction, and maximum Valsalva. The HARP ratios of successful and unsuccessful trials were compared, receiver operating characteristic curves in the prediction of successful trials were constructed, and the cut-off optimizing sensitivity and specificity was identified. Results: A total of 162 women were assessed and 106 were included with 77 successful trials, 49 unsuccessful trials owing to dislodgment or failure to relieve POP symptoms, and 20 unsuccessful trials owing to pain/discomfort. Rest HARP ratio and Valsalva HARP ratio were significantly smaller in the successful trials versus dislodgment/failure to relieve POP symptoms trials (mean rest HARP ratio [SD]: 2.93 [0.59] vs 3.24 [0.67], p = 0.021; median Valsalva HARP ratio (IQR): 4.65 (1.56) vs 5.32 (2.08), p = 0.004). No significant difference was observed between pain/discomfort trials and successful trials. The best cut-off for the prediction of successful trials was Valsalva HARP ratio ≤ 5.00. Conclusions: Unsuccessful fitting trials due to dislodgment/failure to relieve POP symptoms are associated with a small ring pessary with respect to the levator HA. A ring pessary that produces a Valsalva HARP ratio > 5.00 has a higher risk of dislodgment/failure to relieve POP symptoms.