The female reproductive tract microbiome and obesity

High-throughput 16S rRNA sequencing has allowed us to identify novel microorganisms and their relationships in the female reproductive tract. However, in obese patients, the female reproductive tract microbiome, unlike the intestinal microbiome, has been understudied. Here, the literature review analyzes and describes microbiome features in the external genitalia, vagina, cervical canal, uterus, and ovaries in overweight and obese nonpregnant and pregnant females. The microbiome of the lower female reproductive tract in obese patients is characterized by increased bacterial diversity, pH, decreased Lactobacillus abundance, and increased abundance of obligate anaerobes and yeasts of the genus Candida . The endometrial microbiome in overweight and obese patients has been studied only in postmenopause and is characterized by higher Proteobacteria abundance. No data on the characteristics of the ovarian microbiome in obese patients are available. The mechanisms accounting for microbiome changes in obese patients are likely to due to the ability of adipose tissue-derived leptin and estrone to inhibit production of pituitary gonadotropic hormones resulting in blocked ovulation and lowered estradiol production in patients of reproductive age. Consequently, a decline in glycogen synthesis in the vaginal epithelium, decreased Lactobacillus abundance followed by elevated vaginal mucus pH value and number of obligate anaerobes, including those associated with bacterial vaginosis are observed. Weight loss can have a beneficial effect on the state of the vaginal microbiome, restoring normal Lactobacillus abundance.