Analysis of vaginal and endometrial microbiota communities in infertile women with a history of repeated implantation failure.

PURPOSE

To identify specific bacterial communities in vaginal and endometrial microbiotas as biomarkers of implantation failure by comprehensively analyzing their microbiotas using next-generation sequencing.

METHODS

We investigated α- and β-diversities of vaginal and endometrial microbiotas using 16S rRNA gene sequencing and compared their profiles between 145 women with repeated implantation failure (RIF) and 21 controls who lacked the factors responsible for implantation failure with a high probability of being healthy and fertile to identify specific bacteria that induce implantation failure.

RESULTS

The endometrial microbiotas had higher α-diversities than did the vaginal microbiotas ( < .001). The microbiota profiles showed that vaginal and endometrial samples in RIF patients had significantly higher levels of 5 and 14 bacterial genera, respectively, than those in controls. Vaginal rates in RIF patients were significantly lower at 76.4 ± 38.9% compared with those of the controls at 91.8 ± 22.7% ( = .018), but endometrial rates did not significantly differ between the RIF patients and controls (56.2 ± 36.4% and 58.8 ± 37.0%, respectively,  = .79).

CONCLUSIONS

Impaired microbiota communities containing specific bacteria in both the endometrium and vagina were associated with implantation failure. The vaginal rates, but not the endometrial, may be a biomarker for RIF.