Vaginal Microecology Markers Predict Secondary Infection in Abnormal Uterine Bleeding

A combined prediction model evaluating vaginal microecology morphology and functional parameters achieved an area under the curve of 0.902 for detecting secondary vaginal infections in patients with abnormal uterine bleeding, according to prospective study data from researchers at the Second Affiliated Hospital of Soochow University. The combined assessment demonstrated a sensitivity of 88.24 percent and a specificity of 76.62 percent over a six-month follow-up period.

The prospective study enrolled 128 patients diagnosed with abnormal uterine bleeding between April 2021 and April 2023 who had no initial vaginal infection at baseline. Vaginal secretions were collected from each participant to conduct morphological and functional evaluations of the vaginal microecology. Following six months of monitoring, the study cohort was categorized into an infected group of 51 patients and an uninfected group of 77 patients.

Analysis of vaginal secretions revealed distinct differences in baseline microecological characteristics between the two groups. Patients who developed secondary infections exhibited higher vaginal bacterial concentrations than those who remained uninfected. In addition, the infected group showed higher proportions of abnormal pH, abnormal hydrogen peroxide secretion, positive leukocyte esterase, elevated Nugent scores, and increased leukocyte counts, whereas the proportion of gram-positive bacteria was lower.

Correlation evaluations indicated that secondary vaginal infection was positively correlated with vaginal microbiota density grade I plus IV, abnormal pH, abnormal hydrogen peroxide secretion, positive leukocyte esterase, Nugent score, and leukocyte count in vaginal secretions. Conversely, the presence of gram-positive bacteria showed a negative correlation with secondary infection.

The study authors concluded that the vaginal microecology of patients with abnormal uterine bleeding is unbalanced and associated with a high incidence of secondary infection. The researchers reported that combining these morphological and functional parameters offers reference value for early warning and risk evaluation of secondary vaginal infections.

In outlining the clinical background of the study, the investigators explained that abnormal uterine bleeding represents a common gynecological condition capable of disrupting both the natural acidic environment of the vagina and its endogenous self-cleaning mechanisms. The researchers noted that while morphological and functional changes in the vaginal microenvironment occur during abnormal bleeding episodes, the precise predictive value of routine microecological parameters for forecasting subsequent infection had previously remained unclear.

To address this clinical uncertainty, the researchers established a prospective study protocol specifically intended to investigate the current status of vaginal microecology morphology and function in women with abnormal uterine bleeding, assess its direct impact on subsequent infection rates, and analyze its practical utility as an early warning system. In addition to direct cohort comparisons between infected and uninfected patients, the analytical workflow incorporated receiver operating characteristic curve analysis to systematically quantify the diagnostic accuracy, sensitivity, and specificity of the combined parameter model.

The researchers noted that secondary infection may be closely linked to the concentration of vaginal flora categorized as density grade I plus IV, changes in dominant flora composition, abnormal hydrogen peroxide production, elevated Nugent scores, disrupted pH levels, positive leukocyte esterase findings, and elevated leukocyte counts within vaginal secretions.

The investigation was conducted by researchers Ge Ge, Wen Xing, Jianshan Yuan, and corresponding author Beibei Fei from the Second Affiliated Hospital of Soochow University in Suzhou, China. Their research was published in Frontiers in Cellular and Infection Microbiology under the Clinical and Diagnostic Microbiology and Immunology section, following manuscript submission on June 3, 2026, and formal acceptance on September 10, 2026.

Subject of Research: Vaginal microecology morphology and function as early predictors of secondary infection in abnormal uterine bleeding

Article Title: Vaginal microbial ecology in abnormal uterine bleeding: compositional alterations and pathophysiological impact as early predictors of secondary infection

Article References: Ge, G., Xing, W., Yuan, J., & Fei, B. (2026). Vaginal microbial ecology in abnormal uterine bleeding: compositional alterations and pathophysiological impact as early predictors of secondary infection. Frontiers in Cellular and Infection Microbiology, 16, Article 1899052. https://doi.org/10.3389/fcimb.2026.1899052

Image Credits: AI Generated

DOI: 10.3389/fcimb.2026.1899052

Keywords: abnormal uterine bleeding, vaginal microecology, secondary infection, Nugent score, leukocyte esterase, hydrogen peroxide secretion, vaginal pH, ROC analysis, Vaginal, microbial, ecology, abnormal