Polycystic Ovary Syndrome (PCOS) and Bacterial Vaginosis (BV) are two common conditions affecting women’s health, though they impact different body systems. PCOS is a hormonal and metabolic disorder, while BV is an imbalance of the vaginal microbiome. Although they appear distinct, research suggests a connection between the two. This exploration examines whether having PCOS increases the risk of developing BV and the underlying biological mechanisms driving this association.
Understanding Polycystic Ovary Syndrome and Bacterial Vaginosis
Polycystic Ovary Syndrome is an endocrine and metabolic disorder that affects an estimated 6–13% of women of reproductive age worldwide. The condition is characterized by an excess of androgens and often includes irregular menstrual cycles or a lack of ovulation. Diagnostic features of PCOS may include the presence of multiple small follicles on the ovaries, as well as signs of hyperandrogenism such as excess hair growth or acne.
Bacterial Vaginosis is a disruption of the natural vaginal environment. A healthy vaginal environment is normally dominated by protective bacteria, primarily Lactobacilli, which produce lactic acid and maintain an acidic pH. BV occurs when there is a significant decrease in these protective Lactobacilli and an overgrowth of diverse anaerobic bacteria, such as Gardnerella vaginalis and Prevotella species. This microbial shift, known as dysbiosis, leads to a less acidic environment, making the area vulnerable to infection.
The Scientific Link Between PCOS and BV Risk
Epidemiological studies suggest that women diagnosed with PCOS have a higher prevalence of vaginal infections, including BV, compared to the general population. The hormonal and metabolic changes associated with PCOS appear to create conditions that make the development of BV more likely.
This increased susceptibility is supported by findings that women with PCOS often exhibit a higher diversity in their vaginal microbiome, which is associated with a less stable environment. Research has shown a decreased abundance of protective Lactobacillus species in women with PCOS, alongside an increase in bacteria commonly associated with BV, such as Mycoplasma and Prevotella. This imbalance indicates that PCOS-related factors indirectly drive a state of vaginal dysbiosis.
Biological Mechanisms Driving the Connection
The link between PCOS and BV is driven primarily by the syndrome’s impact on hormones and metabolism. A significant feature of PCOS is insulin resistance, which affects approximately 50–80% of women with the condition. This resistance leads to hyperinsulinemia, where the body produces excessive insulin to compensate for the impaired cellular response. High insulin levels exacerbate hyperandrogenism by stimulating the ovaries to produce more androgens and by inhibiting the liver’s production of Sex Hormone-Binding Globulin (SHBG).
The resulting increase in free androgens and insulin resistance can alter the local vaginal environment. Estrogen stimulates the accumulation of glycogen in the vaginal epithelial cells, which is the primary nutrient source for protective Lactobacilli. The hormonal fluctuations and metabolic disturbances seen in PCOS disrupt this glycogen pathway. A reduction in available glycogen suppresses the growth of Lactobacilli, leading to a less acidic vaginal pH. This shift creates a more favorable environment for the overgrowth of anaerobic bacteria, the hallmark of BV.
Furthermore, the chronic, low-grade inflammation associated with metabolic dysfunction in PCOS may contribute to the destabilization of the vaginal microbial environment. This inflammation increases vulnerability to recurrent BV.
Integrated Management Strategies
Managing the increased risk of BV in women with PCOS requires an integrated approach that addresses both the infection and the underlying metabolic and hormonal drivers. Standard BV treatment involves a course of antibiotics, such as metronidazole, to eliminate the overgrowth of harmful bacteria. For women with PCOS, recurrence rates can be high due to persistent internal factors affecting the vaginal environment.
Following antibiotic treatment, the next step involves actively restoring the vaginal microbiome to prevent recurrence. This includes the use of probiotics containing Lactobacillus species to re-establish a protective, acid-producing flora.
The second prong of management is addressing the core features of PCOS. Interventions focused on improving insulin sensitivity, such as dietary modifications, increased physical activity, or insulin-sensitizing medications like metformin, can help. By stabilizing metabolic health and reducing hyperandrogenism, these treatments promote a healthier, more stable vaginal environment.