Species-level analysis of intrauterine cavity fluid microbiota in cesarean scar disorder.

AIM: Cesarean scar disorder, associated with secondary infertility, is frequently accompanied by intrauterine cavity fluid. This study aimed to analyze the bacterial flora in the intrauterine cavity fluid of patients with cesarean scar disorder.

METHODS

This retrospective study included 68 patients diagnosed with cesarean scar disorder complicated by secondary unexplained infertility and intrauterine cavity fluid. Intrauterine cavity fluid samples were analyzed using 16S ribosomal RNA sequencing. Samples were categorized as Lactobacillus-dominant (≥ 90%) or non-Lactobacillus-dominant (<90%) and further stratified into eubiosis or dysbiosis. Eubiosis was defined as > 90% Lactobacillus species excluding Lactobacillus iners; all other microbiota compositions were defined as dysbiosis.

RESULTS

Of the 68 cases, 32 (47.1%) were classified as Lactobacillus-dominant and 36 (52.9%) as non-Lactobacillus-dominant. Clinical characteristics did not differ significantly between the two groups. Fifty-six cases (82.4%) were classified as dysbiosis and 12 (17.6%) as eubiosis, with no significant clinical differences between the two groups.

CONCLUSIONS

Species-level analysis revealed a high prevalence of dysbiosis in patients with cesarean scar disorder. These findings suggest that species-level evaluation is essential when examining intrauterine flora in cesarean scar disorder.