Fatty acid composition in the vaginal tract of cis-gender women: canary in coal mines for reproductive health?

The vaginal tract of cis-gender women of reproductive age is inhabited by communities of bacteria generally dominated by one of four Lactobacillus species. These bacteria are important for the reproductive health of women and favor better outcomes, including fertility, pregnancy leading to term and protection against infections. Past studies have focused on the role of carbohydrates in the balance of vaginal communities, and the role of fatty acids has been underestimated. However, small- to long-chain fatty acids present few properties that, in combination with sugar metabolism, affect the outcomes of the health or disease within the vaginal communities. Herein, we explore the origins of fatty acids in the vaginal tract as well as their roles in the bacterial life cycle in this environment. We also detail the putative impact of vaginal FAs on S. aureus, one of the etiologic agents of aerobic vaginitis. Finally, we discuss their potential for prevention or therapy in women of reproductive age.