Characterization of Vaginal Microbial Colonization in Cervical Insufficiency Patients and Its Relation to Preterm Birth: An Observational Cohort Study

Abstract

Background: Cervical insufficiency is one of the main risk factors for preterm birth. It has been suggested that a more diverse vaginal microbial colonization might lead to cervical insufficiency and subsequently further increase the risk for preterm birth. To date, the microbial colonization in women with cervical insufficiency has not been sufficiently categorized. Therefore, this study is aimed at describing the vaginal microbial colonization in this high-risk collective and exploring a possible association with preterm birth. Methods and Study Design: All women treated for cervical insufficiency from June 2021 until March 2024 at the Division for Obstetrics and Feto-Maternal Medicine of the Medical University of Vienna were evaluated for inclusion. Vaginal bacterial/fungal culture results during pregnancy were used for the characterization of the vaginal microbial colonization and categorized in 17 predefined microbial groups. Results: We included 118 women with cervical insufficiency with available vaginal culture results, of whom 58.5% experienced preterm birth. Lactobacillus spp., coagulase-negative staphylococci, Enterococcus spp. and Ureaplasma spp. were the most frequently detected microorganisms. Further, we conducted a secondary exploratory analysis of the association of each individual microbial group with preterm birth, which found an absence of lactobacilli (p = 0.047) and the presence of a more diverse microbial composition with Gram-negative anaerobes, Ureaplasma spp. and Enterococcus spp. to be more frequent in PTB. Conclusion: Cervical insufficiency is associated with a diverse vaginal microbial colonization. Especially colonization with coagulase-negative staphylococci, Ureaplasma spp., and Enterococcus spp. seems to play an important role in cervical insufficiency. Lactobacillus spp. absence was associated with subsequent preterm birth.