Effectiveness of intravaginal electrical stimulation combined with electromyography biofeedback-mediated pelvic floor muscle training for postpartum symptomatic pelvic organ prolapse: protocol for the PROSPECT randomized trial.

Background: Pelvic organ prolapse (POP) is seen in up to 30-70% of women presenting for routine gynecology care and 10% of women suffering from bothersome POP symptoms. Vaginal childbirth is one of the most prominent contributing factors for POP. Pelvic muscle training (PFMT) is considered effective to improve mild to moderate POP symptoms. In addition, higher-intensity, supervised PFMT aided by biofeedback and electrical stimulation may confer greater benefit. However, the long-term efficacy of the PFMT combined with electromyography biofeedback is unknown, which indicates the need for further evidence.

Methods: This multicenter randomized controlled trial compares the effectiveness and cost-effectiveness of conventional PFMT versus biofeedback-mediated PFMT plus neuromuscular electrical stimulation (NMES) for postpartum symptomatic POP women. The primary outcome is the proportion of patients with the improvement of at least one POP-Q stage at 36 months after randomization. The primary economic outcome measure is incremental cost per quality-adjusted life year at 36 months. Two hundred seventy-four women from four outpatient medical centers are randomized and followed up with pelvic floor examination, questionnaires, and pelvic ultrasonography imaging. All participants are arranged for three appointments over 12 weeks. NMES and electromyography biofeedback via intravaginal probe are added to PFMT for participants in the biofeedback-mediated PFMT group. Group allocation could not be blinded from participants and healthcare staff that deliver intervention but remain masked from medical staff that carry out PFM assessment. An intention-to-treat analysis of the primary outcome will estimate the difference of the proportion of POP-Q stage improvement between the trial groups right after the intervention, and during the follow-up until 36 months, using the chi-square test and multilevel mixed models respectively. A logistic regression analysis was used for adjusting for important baseline variables that are unbalanced.

Discussion: The trial results will provide evidence of the effectiveness of electromyography biofeedback-mediated PFMT in improving women's POP-Q staging, quality of life, and cost-effectiveness.

Trial Registration: CCTR Registry ChiCTR210002171917 . Registered on March 6, 2019.