Abnormal vaginal flora and spontaneous preterm birth in high-risk singleton pregnancies with cervical cerclage

Abstract

Objective

To investigate abnormal vaginal and suture-based bacterial flora for associations with spontaneous preterm birth in high-risk singleton pregnancies with an ultrasound-indicated or emergency cervical cerclage.

Materials and methods

A retrospective study of 196 singleton pregnancies with an ultrasound-indicated or emergency cerclage at the Royal Women’s Hospital, Australia, from 2004 to 2018. High vaginal swabs were collected regularly between 14 and 26 weeks’ gestation, including pre- and post-cerclage insertion, and sent for microscopy and culture. Cervical suture was cultured upon removal. Primary outcomes were spontaneous preterm birth <37, <34 and <30 weeks.

Results

43.4% (85/196) of women delivered preterm. The acquisition and persistence of vaginal Escherichia coli following cerclage insertion were independently associated with spontaneous preterm birth <37 weeks (p = .0225, p = .0477). Escherichia coli growth from the cervical suture upon removal was associated with spontaneous preterm birth <34 weeks (p = .0458). The acquisition of vaginal mixed anaerobes post-cerclage was independently associated with spontaneous preterm birth <34 weeks (p = .0480)

Conclusion

For singleton pregnancies with an ultrasound-indicated or emergency cerclage, the presence of vaginal or suture-based Escherichia coli following cerclage insertion yields increased risk of cerclage failure and spontaneous preterm birth.

Keywords:

• Preterm delivery
• cervical cerclage
• ultrasound-indicated cerclage
• emergency cerclage
• vaginal flora
• bacteria
• outpatient clinics
• prenatal care

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Acknowledgements

Ms. Sharyn Bonnici, Research and Duplicate UR Clerk, The Royal Women’s Hospital, Melbourne, VIC 3052, Australia.

Disclosure statement

No potential conflict of interest was reported by the author(s).