Vaginal microbiota composition and pH

The vaginal microbiota composition and pH constitute a dynamic biological system that serves as a critical barrier against infection. In healthy reproductive-age women, the environment is typically dominated by Lactobacillus species, which maintain a low pH (3.8–4.5) through the production of lactic acid (Ravel et al., 2011, PNAS). This acidic environment, supplemented by antimicrobial peptides and hydrogen peroxide, inhibits the overgrowth of anaerobic bacteria and the colonization of pathogens (Coudray & Madhivanan, 2020, Sex Transm Dis). Disruptions to this balance, known as dysbiosis or bacterial vaginosis, are characterized by a decrease in Lactobacilli and an increase in microbial diversity and pH. Such imbalances are clinically significant as they increase susceptibility to sexually transmitted infections, including HIV, and are linked to adverse pregnancy outcomes like preterm birth (Borgdorff et al., 2014, AIDS). Therapeutic interventions target this system by either eliminating overrepresented anaerobes with antibiotics or replenishing beneficial bacteria using live biotherapeutic products (Cohen et al., 2020, NEJM). Additionally, acidifying agents and prebiotic formulations are used to directly lower the pH and support the growth of commensal flora.

Other names

Vaginal microbiomeVaginal floraVaginal ecosystemVaginal pH

Restoration of Lactobacillus dominance and maintenance of an acidic environment (pH < 4.5) to inhibit the overgrowth of anaerobic bacteria and pathogens.