The effect of oral progestogens on the intestinal microbiota composition in patients with endometriosis: pilot study

Today, the contribution of the microbiota to the genesis of many diseases, including endometriosis, is widely discussed. However, the literature data on the microbiological composition of endometriosis are contradictory. In addition, data indicating the effect of conservative therapy on the microbiological composition are limited only to estrogen-containing drugs, while there is no data on the effect of progestogens. Objective: to evaluate the composition of the intestinal microbiota of patients with external genital endometriosis on oral progestogen therapy. A single-stage pilot study was conducted, which included 17 patients with external genital endometriosis (average age 30.9 (7.8) years, average body mass index 20.2 (2.0) kg/m 2 ). The women received oral progestogen therapy (dienogest at a dose of 2 mg per day in a continuous mode). Microbiological examination of faecal samples by culturomics methods with inoculation on selective and non-selective nutrient media, followed by species identification of microorganisms, was carried out using time-of-flight mass spectrometry (MALDI-TOF MS) at two points: initially and after 6 months of taking dienogest. Dienogest therapy showed an improvement in a number of microbiological indicators of the intestinal microbiota in the form of a tendency to increase species and taxonomic diversity, a decrease in the Bacillota / Bacteroidota index, and a decrease in the titer of conditionally pathogenic microorganisms Staphylococcus spp. and increased colonization of symbiotic bacteria of the Collinsella aerofaciens and Lactobacillus spp. Thus, dienogest therapy can have both a direct and indirect effect on the composition of the intestinal microbiota of patients with external genital endometriosis, which was demonstrated by the results of the study.