Multicenter Prospective Cohort Study of Cervical Pessary for Preventing Spontaneous Preterm Birth

Objective  To compare the efficacy of cervical pessary versus vaginal progesterone gel in preventing spontaneous preterm birth in individuals with a short cervix.

Methods  This multicenter prospective cohort study enrolled 609 pregnant women with cervical length ≤25 mm at 13-28 weeks of gestation from six hospitals in China between August 2020 and June 2023. Participants were divided into the cervical pessary group and the progesterone group. Maternal and neonatal outcomes were compared between the two groups.

Results  In the overall population, univariate analysis showed that the cervical pessary group had a longer gestational prolongation (70.98 ± 36.43 d vs. 56.68 ± 33.91 d, P < 0.0001), and lower rates of preterm birth < 34 weeks, < 37 weeks, and spontaneous preterm birth < 37 weeks (P < 0.05). Multivariate analysis indicated that the cervical pessary group had longer gestational prolongation (β =－11.02, 95% CI －15.89 to －6.15) and a lower risk of preterm birth < 34 weeks (odds ratio OR = 1.908, 95% CI 1.209-3.010). In singleton pregnancies, univariate analysis revealed that the cervical pessary group had longer gestational prolongation (77.16 ± 37.71 d vs. 67.34 ± 36.64 d, P = 0.010), lower rates of preterm birth < 28 weeks and spontaneous preterm birth < 28 weeks (P < 0.05), as well as higher neonatal birth weight and better Apgar scores at 1 and 5 minutes (P < 0.05). However, multivariate analysis showed no significant differences between the two groups in preterm birth endpoints, gestational prolongation, or neonatal outcomes (P > 0.05). In twin pregnancies, univariate analysis showed that the cervical pessary group had longer gestational prolongation( 56.02 ± 28.15 d vs. 42.78 ± 23.73 d, P > 0.001), but paradoxically higher rates of spontaneous preterm birth < 28 weeks and < 32 weeks (P < 0.05). Multivariate analysis demonstrated that the cervical pessary group had longer gestational prolongation (β = －17.40, 95% CI －24.99 to －9.81) and a lower risk of preterm birth < 34 weeks (OR = 5.136, 95% CI 2.246-11.744).

Conclusion  For pregnant women with a cervical length of ≤ 25 mm, cervical pessary is more effective than progesterone in prolonging gestation and can reduce the incidence of preterm birth before 34 weeks.