The Efficacy of Botulinum Toxin A Injection in Pelvic Floor Muscles in Chronic Pelvic Pain Patients: A Double-Blinded Randomised Controlled Trial

Objective

To evaluate and compare the efficacy and safety of Botulinum Toxin A (BTA) injections versus placebo injections, combined with pelvic floor muscle therapy (PFMT), in women with chronic pelvic pain (CPP).

Design

Randomised, double-blinded clinical trial (January 2020–April 2023).

Setting

This multicentre study was conducted at four hospitals in the Netherlands.

Population and Sample

Ninety-four women with CPP and increased pelvic floor muscle tone despite previous PFMT, were enrolled.

Methods

Participants received either BTA injections (100 units) or placebo injections into the pelvic floor muscle, followed by four PFMT sessions.

Main Outcomes and Measures

Primary outcomes included the number of women with at least a 33% reduction in pain and those reporting (very) much improvement of their pain. Secondary outcomes covered quality of life and pelvic floor function. Follow-up visits were scheduled at 4, 8, 12, and 26 weeks post-treatment. Mixed models for repeated measurements were used for analysis.

Results

A 33% reduction or more in average pain score was reported by 15 participants (33%) after BTA treatment and 9 participants (20%) after placebo treatment (odd ratio placebo/BTA 1.88; 95% CI 0.72–4.90, p = 0.19). In both groups, 8 women (17%) reported their improvement as (very) much better (odd ratio placebo/BTA 0.947; 95% CI 0.32–2.80, p = 0.92). Pelvic floor resting activity decreased significantly after BTA treatment compared to placebo (p = 0.001).

Conclusion

The results from this study do not support the use of BTA injections in the management of CPP in women.