The invisible imbalance: why your microbiome's chemistry matters

Science · Published 23 October 2026 Swipe more like this →

In short: Bacterial vaginosis is often misunderstood as a simple infection. In reality, it is a complex shift in your internal ecosystem. When the delicate balance between beneficial and harmful bacteria tips, it can lead to persistent issues that require more than just a quick fix.

Bacterial vaginosis (BV) is defined by a disruption in the vaginal microbiome—the community of bacteria naturally residing in the vagina. Under normal conditions, 'good' bacteria known as lactobacilli maintain a healthy environment. BV occurs when 'bad' bacteria, specifically anaerobes, begin to grow more quickly than the lactobacilli, creating an imbalance in the microbial population.

While many people associate vaginal issues with sexually transmitted infections, BV is not an STI. However, research suggests that sexual activity can alter the vaginal chemistry, making bacterial overgrowth more likely. Conversely, it is important to note that BV is not contagious; it cannot be contracted from hot tubs, swimming pools, toilet seats, or by touching surfaces touched by someone with the condition.

The clinical presentation of BV can be deceptive. While the hallmark sign is often a thin, watery, greyish-white discharge with a strong fishy smell (particularly after sex), up to 84% of people with the condition may experience no symptoms at all. Because symptoms overlap with other conditions like yeast infections—which typically lack a strong odor and cause significant itching—professional diagnosis via a healthcare provider is essential.

Treatment typically involves antibiotics, but the condition is known for its tendency to recur within a few months. For those who experience recurring cases—defined as more than four times in a year—healthcare providers may prescribe long-term antibiotic gels to help stabilize the environment and prevent the imbalance from returning.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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