Reproductive Tract Microbiota Dysbiosis and Hormonal Imbalance: Interrelation in the Pathogenesis of Infertility

Abstract

Background. Infertility in reproductive-aged women is a major global health issue, with microbial dysbiosis and hormonal imbalance playing key roles in its pathogenesis. Objective. To evaluate the relationship between localization of reproductive tract microbiota dysbiosis and hormonal profile in infertile women. Materials and Methods. A total of 120 infertile women aged 20–40 years were enrolled. Four groups were formed: vaginal–cervical dysbiosis (n=30), endometrial–tubal dysbiosis (n=30), ovarian dysbiosis (n=30), and a healthy control group (n=30). Microbiota composition was assessed by 16S rRNA sequencing, while serum hormones (FSH, LH, E₂, progesterone, AMH, prolactin) were measured using the Immulite 2000 XPI immunoassay system. Results. Ovarian dysbiosis was associated with increased FSH (10.6 mIU/mL) and LH (8.1 mIU/mL), decreased AMH (1.12 ng/mL), estradiol (142 pg/mL), progesterone (8.7 ng/mL), and elevated prolactin (20.8 ng/mL) (p<0.001). Endometrial–tubal dysbiosis correlated with low progesterone, while vaginal–cervical dysbiosis was linked to hyperprolactinemia. Conclusion. The closer the dysbiosis is localized to the ovaries, the more pronounced are hormonal disturbances, ovarian reserve depletion, and reduced fertility.