Distinctive subpopulations of the intestinal microbiota are present in women with unexplained chronic anovulation.

RESEARCH QUESTION: Do gut microbiota associate with the ovulatory cycle in women showing normogonadotrophic anovulation? In humans, the gut microbiota affects diverse physiological functions and dysbiosis (microbial imbalance) may lead to pathological syndromes. However, there is comparatively little information on the relevance of gut microbiota to reproductive functions in women. Here, a group of women with idiopathic chronic anovulation were examined, who do not exhibit any apparent endocrinological disorder, as they are suitable for investigating the relationship between intestinal bacteria and ovulatory disorders. DESIGN: A prospective observational cohort study was performed on two groups of women who did not exhibit apparent endocrinological disorders but showed either irregular menstrual cycles (IMC group) or normal menstrual cycles (controls). The bacterial composition of faeces from rectal swabs from the women was analysed using next-generation sequencing based on bacterial 16SrRNA genes. RESULTS: A metagenomic analysis indicated that the two groups of women had significant differences in 28 bacterial taxa in their faeces. Prevotella-enriched microbiomes were more abundant in the IMC group, whereas Clostridiales, Ruminococcus and Lachnospiraceae (butyrate-producing bacteria) were present at lower levels in the IMC group. CONCLUSIONS: Distinctive subpopulations of intestinal microbiota were identified in women with unexplained chronic anovulation. The results indicate that gut microbiota could be associated with ovarian functions.