Botox: A New Treatment for Endometriosis Pain?

When botulinum toxin A (Botox) is mentioned, it is often thought about in terms of cosmetic surgery – but there are many other potential applications for it as well. Botox weakens or paralyzes muscle, so it can help with certain muscle-related conditions. Now, new research has shown that women with chronic pelvic pain (CPP) associated with endometriosis may benefit from Botox injections.¹

What is chronic pelvic pain (CPP?)

CPP is defined as non-menstrual pelvic pain that lasts for 6 months or longer.² It is estimated that 15 to 20 percent of reproductive-age women have CPP, and for those who have surgery for the condition, one-third are found to have endometriosis.² The number of women with endometriosis who don’t get surgery for their CPP may be even higher. Despite optimal treatment with surgery and/or hormones, many women still experience CPP and some even have muscle spasms of the pelvic floor.³

CPP can have a significant impact on a person’s quality of life, which makes effective treatment necessary.

How can Botox help?

A 2020 clinical trial study included a group of premenopausal women, ages 18 to 50, with an average age of 30. All had CPP and documented endometriosis.¹ Their pelvic pain was directly due to endometriosis and not another primary medical condition. The 100-units Botox (or saline, in the placebo group) was injected trans-vaginally into pelvic floor muscles.¹ The exact placement was based on where the study participant had pain and spasms.

A 300-unit dose of Botox is typical when treating muscle conditions like spasticity or dystonia, and 100-units, the dose in the study is considered low.¹ The injection takes approximately one week to take effect and can last up to 3 months. Women in the study had the choice to request another injection at any time up to a year after the first month.

Changes in pain intensity, pain medication use, disability, and muscle spasm were assessed at multiple visits up to 1 year post-injection.³ Thirteen women were injected with Botox; prior to the injection, 11 of them had spasms and reported moderate pain.³

By 4-8 weeks post-injection, spasm was gone or less widespread in all participants and 11 rated their pain as absent or mild. Relief lasted 5-11 months in 7 of the 11 participants who made it to the 1 year follow-up. In the 8 women who reported at least moderate disability pre-injection, disability decreased in 6 of them.³ Adverse effects were mild and resolved on their own.

While this is a promising study, it was also a very small study, and more research needs to be done. For those without pelvic floor muscle spasm, this may not be an appropriate or effective treatment.

Things to consider

The results of the study seem to show that Botox may be a useful treatment for endometriosis-related CPP. The pain may be due to muscle spasms, and Botox not only relieves the spasms and subsequent endometriosis pain, but also reduces pain-related disability. Overall, this may improve a woman’s general quality of life.

If you have endometriosis and pain caused by pelvic floor muscle spasms, talk with your doctor about this research, and when this treatment may be available for use. It may not be right for everyone, but your doctor can discuss your individual case and symptoms and determine whether this might be appropriate when available.