Gut Microbiota Changes After Hormonal or Surgical Treatment for Endometriosis

Although studies have suggested a link between gut microbiota and endometriosis pathophysiology, the effects of treatment for endometriosis remain unclear.

In this prospective observational study, 27 patients with stage III/IV endometriosis and 17 healthy controls provided a total of 56 fecal samples. In endometriosis patients, gut microbiota profiles were analyzed before and after hormonal therapy or surgery to assess treatment-related changes. 16S rRNA gene sequencing was used for microbiota analysis.

No differences in α- or β-diversity were observed between the endometriosis and control groups, although patients with endometriosis had high levels of Acidaminococcus, Lachnoclostridium, and Paraprevotella and low levels of Odoribacter (all p < 0.05). Among the eight patients who received hormonal therapy, no significant changes in α- and β-diversity were observed between the pre- and post-treatment samples. A comparison of samples from the same individuals showed an increase in Blautia, which is associated with mental health stability, and a decrease in Sutterella, which is involved in regulating the intestinal barrier. In an exploratory analysis of patients without recurrence after surgery (n = 4), α-diversity significantly increased (p = 0.035), with stable β-diversity. Postsurgical increases were observed in 10 genera, including six inflammation-related taxa; five (Flavonifractor, [Eubacterium]_brachy_group, Hungatella, Incertae_Sedis, and Fournierella) are associated with anti-inflammatory effects.

Hormonal therapy for endometriosis may help not only to control lesions but also to support mental health. Surgical treatment may alter the composition of inflammation-associated gut bacteria; however, these exploratory results from a small cohort should be interpreted with caution. Further studies with larger sample sizes are warranted.