Twin pregnancies are characterized by a fivefold higher risk of preterm birth compared to singletons, contributing disproportionately to neonatal morbidity and long-term neurodevelopmental disabilities. Cervical insufficiency is a critical, modifiable risk factor in this population. Despite the prevalence of these interventions, high-quality comparative data specifically for twin gestations remain scarce, leading to significant variations in clinical practice. This study addresses a vital gap in obstetric protocols by providing quantitative evidence on whether invasive surgical intervention (cerclage) or a non-invasive device (pessary) offers better protection against the mechanical stressors of a twin pregnancy. As the incidence of multifetal gestations rises due to assisted reproductive technologies, establishing standardized, evidence-based guidelines for cervical support is paramount. Reducing the rate of extreme preterm birth from 15% to even 10% in twins would result in substantial healthcare cost savings and, more importantly, significantly improved life-long outcomes for thousands of neonates annually.
The primary objective was to compare the efficacy of cervical cerclage and Arabin vaginal pessary in prolonging pregnancy and reducing spontaneous preterm birth before 32 weeks in twin gestations with a cervical length under 25 mm.
This retrospective multicenter cohort study analyzed 450 women with DCDA twin pregnancies and a sonographic cervical length <25 mm identified between 18+0 and 23+6 weeks of gestation. Participants were divided into two groups: the Cerclage group (n=210), who underwent McDonald cerclage, and the Pessary group (n=240), who received a silicone Arabin pessary. Exclusion criteria included monichorionic monoamniotic gestations, major fetal anomalies, and evidence of clinical chorioamnionitis or active labor at presentation. The primary endpoint was spontaneous preterm birth (sPTB) before 32 weeks' gestation. Secondary endpoints included sPTB <28 and <34 weeks, mean gestational age at delivery, and a composite of adverse neonatal outcomes (NICU admission, respiratory distress syndrome, intraventricular hemorrhage, and neonatal death). Statistical significance was determined using Chi-square tests for categorical variables, Student’s t-tests for continuous data, and Cox proportional hazards regression to calculate Odds Ratios (OR) with 95% Confidence Intervals (CI). Adjusted models accounted for maternal age, parity, and initial cervical length.
The mean gestational age at delivery was significantly higher in the Cerclage group compared to the Pessary group (33.8 ± 3.1 vs. 31.2 ± 4.4 weeks; p < 0.001). Spontaneous preterm birth before 32 weeks occurred in 18.1% (38/210) of the Cerclage group versus 31.7% (76/240) of the Pessary group (Adjusted OR 0.48; 95% CI, 0.31–0.74; p = 0.002). For delivery before 28 weeks, the cerclage cohort maintained a lower incidence (7.1% vs 14.2%; p = 0.018). The mean latency period from intervention to delivery was 11.4 weeks for cerclage compared to 8.6 weeks for the pessary. Neonatal outcomes mirrored these findings; the composite adverse neonatal outcome rate was significantly lower in the Cerclage group (22.3% vs 38.5%; p < 0.001). Notably, the rate of premature rupture of membranes within 48 hours of the procedure was higher in the cerclage group (2.4% vs 0%, p = 0.02), though this did not offset the overall benefit of the surgical intervention in prolonging the gestation.
In twin pregnancies with a shortened cervix, cervical cerclage demonstrated a statistically significant advantage over the vaginal pessary in preventing spontaneous preterm birth before 32 weeks of gestation. The observed reduction in neonatal intensive care unit admissions and higher birth weights in the cerclage cohort suggest superior mechanical stability compared to the displacement of pressure offered by the pessary. While the vaginal pessary remains a non-invasive alternative with a lower risk of immediate procedural complications like membrane rupture, its efficacy appears limited in high-risk multifetal gestations. Clinicians should prioritize cerclage for DCDA twin pregnancies when cervical shortening is detected between 18 and 24 weeks. Future prospective randomized trials should focus on biochemical markers to further refine candidate selection for these mechanical interventions to optimize maternal and neonatal safety.