Endometriosis is a painful condition that affects 176 million people worldwide, according to the Journal of Endometriosis. It happens when tissue similar to that which forms the lining of the uterus grows outside of the uterine cavity. In a very small pilot study, scientists at the National Institute of Neurological Disorders and Stroke (NINDS) may have found a surprising way to offer relief for chronic pelvic discomfort: Botox injections.
Pain associated with endometriosis often persists even after the growths have been treated with hormonal surgery and therapy. In the placebo-controlled clinical trial, researchers looked at women who’d undergone surgery and were taking hormones to suppress menses (the blood discharged from the uterus during menstruation). Those whose pain persisted after treatment were given either an injection of botulinum toxin (aka Botox) or saline.
A month later, the 13 participants chose to receive the injection of botulinum toxin on a monthly basis for at least four months—and the results were pretty remarkable. For all subjects, fewer to no muscle spasms occurred during their follow up treatment, and 11 out of the 13 said their pain was mild or gone entirely. Plus, more than half of the participants reduced their use of pain medication.
Botox works by blocking the nerve signals so that the muscles in the injected area cannot contract. While past research on the toxin has indicated that it could help women experiencing chronic pelvic pain, this is the first time Botox has been tested specifically to ease the pain of endometriosis. “These findings suggest that pelvic floor muscle spasm may be experienced by women with endometriosis and contribute to pain persisting after standard treatment,” writes Kate Anderton, BSc, a biomedical sciences graduate from Lancaster University.
Barbara Karp, MD, a neurologist and program director at NINDS, points out that more research will need to be conducted before best patient practices can be standardized in the medical space. “We know that many doctors are using botulinum toxin to help their patients, but everyone uses slightly different techniques and methods, including different brands of toxin and various doses,” she says. “This study will begin to provide rigor to help ensure standardized protocols and treatment in pelvic pain.”