Effects of vaginal microbiota and cervical cerclage on obstetric outcomes of twin pregnancies with cervical incompetence: a retrospective study

Abstract

Purpose: To determine the role of vaginal microbiota in the efficacy of cervical cerclage in obstetric outcomes of twin pregnancies.

Methods: This retrospective study enrolled 68 twin pregnant women diagnosed with cervical incompetence (CIC) and 68 twin pregnancies without CIC. The CIC group was further divided into two subgroups: cerclage group (n = 51) and non-cerclage group (n = 17), according to whether cervical cerclage was performed in the second trimester. Data of vaginal microbiota and obstetric outcomes were collected and compared.

Results: Cervical incompetence had harmful effect on both pregnancy outcomes and vaginal microecology, characterized by earlier gestational week at delivery (30.3 ± 5.6 vs 35.6 ± 1.1, P < 0.001), a lower birth weight of newborns (OR 0.40; 95% CI 0.22-0.74), a higher vaginal pH value (OR 0.11; 95% CI 0.04-0.30) and a lower abundance of Lactobacillus (OR 0.34; 95% CI 0.17-0.70). In addition, compared with the vaginal microbiota after cerclage, less normal diversity of bacterial flora (OR 0.35; 95% CI 0.12-1.01), less Lactobacillus (OR 0.40; 95% CI 0.18-0.91) and more Gardnerella vaginalis (OR 18.92; 95% CI 2.38-150.35) appeared before cerclage. Besides, the unhealthy vaginal environment also had an unfavorable influence on the neonatal outcomes, increased neonatal mortality rate was observed in the group of vaginal pH > 4.5 (P < 0.05). Fortunately, compared with the non-cerclage group, the cerclage group had a longer interval from diagnosis to delivery (≥ 8 weeks) and more of the newborns' birth weight were not less than 1500 g (P < 0.05).

Conclusion: A healthy vaginal environment is essential to improve the obstetric outcome for twin pregnancies with cervical cerclage.

Keywords: Cervical cerclage; Microbiota; Pregnancy outcome; Twin pregnancy; Uterine cervical incompetence.