(1223) Cervicovaginal Microbiome in Pre vs Post Cerclage Placement

Though an association between changes in the cervicovaginal microbiome (CVM) and preterm birth has previously been demonstrated, the impact of cerclage placement on the CVM is poorly understood. Our objective was to assess significant changes in CVM due to cerclage placement, and association of CVM makeup with preterm delivery in patients with cervical insufficiency requiring cerclage placement.

Study Design:

This was a prospective cohort study of singleton, non-anomalous pregnancies from 2022-2023 at two tertiary care centers. We enrolled 22 subjects receiving ultrasound or physical exam indicated cerclage, and 20 subjects with no prior preterm delivery and a normal cervical length as controls. Cervicovaginal fluid samples were collected prior to, and 1-2 wks post cerclage placement for the study group, and during routine anatomical surveys for the control group. Samples were analyzed using 16S rRNA gene sequencing. 

Results:

We detected no significant difference in Shannon diversity between study and control groups. However, a significant difference in distribution was observed in Shannon diversity between preterm and term deliveries (p=0.01, Graph1). There were significant differences in differential abundance of 14 taxa in study vs control groups, and 4 taxa in preterm vs term deliveries (Table 1).

When comparing samples pre vs post cerclage placement, no significant difference was observed in Shannon diversity. However, a significant difference in distributions was observed in beta diversity between these samples (p=.04). There were no differences in specific taxon abundance between pre and post cerclage samples.

Conclusion:

In a diverse patient population, differences in CVM distribution are associated with preterm delivery. The abundance of certain taxa may be associated with cervical insufficiency and preterm birth. Though cerclage placement did not implicate a difference in specific taxa present, it does appear to alter the distribution of the CMV.