Changes in the vaginal environment have been shown to affect rates of Group B Streptococcus (GBS) colonization. It is possible that cerclage, a foreign body, alters the vaginal environment and changes susceptibility to GBS. Our objective was to compare GBS colonization rates in women with and without transvaginal cerclage, as well as among women with a cerclage using Mersilene versus Prolene suture.
This was a single-center retrospective cohort study of all women with singleton gestations undergoing McDonald cerclage with Mersilene or Prolene suture from 1/1/2017 – 12/31/2019. Each woman in the cerclage group was matched with a woman without a cerclage by delivery date. These women formed the control group. Exclusion criteria were no GBS result. The primary outcome was GBS status at time of delivery. Secondary outcomes included rates of chorioamnionitis, maternal sepsis, and neonatal sepsis. Data were analyzed using Mann-Whitney U test, chi-square or Fisher’s exact test, and multivariable logistic regression with p < 0.05 defined as significance
216 women were included in the analysis, 108 in each cohort. The control and cerclage groups differed regarding race, use of vaginal or intramuscular progesterone, obstetric history, and gestational age at delivery. There was no difference in rate of GBS colonization between the cerclage and control groups (Table 1). These findings remained unchanged after adjusting for baseline differences (p=0.76). Among women with a cerclage, there was no difference in rate of GBS colonization by suture type (Table 2). The cerclage group was more likely than the control group to develop chorioamnionitis. There were no significant differences in any of the other secondary outcomes (Tables 1-2).
The presence of a cerclage and cerclage suture type are not associated with differing rates of GBS colonization. Whether cerclage changes the vaginal environment in other ways which could contribute to inflammation or dysbiosis warrants further investigation.
© 2021 Published by Elsevier Inc.