Objective
To investigate the relationship between vaginal microbiota composition and outcome of rescue cervical cerclage.
Design
Prospective observational study.
Setting
Queen Charlotte’s and Chelsea Hospital, London
Population
Twenty singleton pregnancies undergoing a rescue cervical cerclage.
Methods
Vaginal microbiota composition was analysed in women presenting with a dilated cervix and exposed fetal membranes before and 10 days following rescue cervical cerclage and correlated with clinical outcomes.
Main outcome measures
Composition of vaginal bacteria characterised by culture independent next generation sequencing.
Successful cerclage, defined as those resulting in the birth of a neonate discharged from hospital without morbidity.
Unsuccessful cerclage, defined as procedures culminating in miscarriage, intrauterine death, neonatal death or significant neonatal morbidity.
Results
Reduced Lactobacillus spp. relative abundance was observed in 40% of cases prior to rescue cerclage compared to 10% of gestational age matched controls (8/20, 40% vs 3/30, 10%, P=0.017). Gardnerella vaginalis was over-represented in women presenting with symptoms (3/7, 43% vs 0/13, 0%, P=0.03, LDA (log 10) and casesculminating in miscarriage (3/6, 50% vs 0/14, 0%, P=0.017). In the majority of cases (10/14, 71%) bacterial composition was unchanged following cerclage insertionand peri-operative interventions.
Conclusions
Reduced relative abundance of Lactobacillus spp. is associated with premature cervical dilatation, whereas high levels of Gardnerella vaginalis are associated with unsuccessful rescue cerclage cases. The insertion of a rescue cerclage does not affect the underlying bacterial composition in the majority of cases.