Cervical dilation after initial cervical cerclage in twin pregnancies: is repeat cerclage beneficial?

OBJECTIVE: Recently, several studies have shown that ultrasound -indicated cerclage (UIC) might prolong gestation and reduce the risk of spontaneous preterm birth (sPTB) in twin pregnancies.1-3 Cervical dilation after cerclage is not uncommon in clinical practice. Repeat cerclage (RC) has been reported as an option in such cases and might be beneficial for singleton pregnant women.4,5 However, there is limited information on the benefit of placing an RC in women twin pregnancies with cervical dilation. Therefore, we compared perinatal and neonatal outcomes in women who are pregnant with twins with additional high -risk factors associated with preterm birth, whose cervixes dilated after initial UIC, and who did or did not undergo RC. STUDY DESIGN: This retrospective cohort study included twin pregnancies with a cervical length (CL) <= 15 mm, who underwent UIC and whose cervixes dilated <= 4 cm before 28 weeks' gestation during follow-up at the Shanghai First Maternity and Infant Hospital from January 2015 to March 2023; these women had additional highrisk factors associated with premature birth. These factors included a history of previous preterm birth at <34 weeks gestation, previous midterm miscarriage, previous cervical surgery, the use of assisted reproductive technology, etc. We offered RC as a possible option for women with twin pregnancies, whose external orifice of the cervix dilated after initial UIC without signs of labor, placental abruption, or chorioamnionitis. The decision to perform RC placement was made by the pregnant individuals and their families after full consultation with experienced maternalfetal physicians. The patients were divided into 2 groups: an RC (managed with RC) group and a control (expectant management) group. The primary outcome was sPTB before 34 weeks' gestation; the secondary outcomes were the sPTB rate, gestational age (GA) at delivery, pregnancy latency, and neonatal outcomes. The results of the primary and secondary outcomes are presented as odds ratios (ORs) or the mean difference (MD) with a 95% confidence interval (CI). Multivariate logistic regression, with the results presented as adjusted ORs (aORs) with 95% CIs, was performed to identify risk factors associated with sPTB. The risk of sPTB was assessed by Kaplan Meier analysis, in which GA was the time scale and delivery was the event. RESULTS: A total of 36 twin pregnancies met the inclusion criteria; 12 underwent RC, and 24 were managed expectantly. There was no difference in patient demographics between the groups (Table). The mean GA and CL at initial UIC were not significantly different between the groups. The mean GA at cervical dilation was comparable between the groups (25.570.99 vs 26.03 +/- 1.47 weeks; P=.34). The dilation of the cervix was also comparable: 13.08 +/- 3.78 vs 11.62 +/- 2.31 mm (P=.24). In the RC group, the GA at delivery was significantly greater (33.52 +/- 2.63 vs 31.26 +/- 2.68 weeks; P=.024), and the pregnancy latency after RC was significantly greater (55.67 +/- 19.35 vs 36.63 +/- 20.46 days; P=.011) than that in the control group. The incidence of sPTB at <34 weeks gestation was significantly lower in the RC group (50.00% vs 87.50%; aOR, 0.084; 95% CI, 0.008-0.88; P=.036). The Kaplan -Meier curves generated for GA at delivery and the log -rank test showed a significant increase in pregnancy prolongation in the RC group compared with the control group (P<.05) (Figure). For neonatal outcomes, the average birthweight was significantly greater in the RC group than in the control group (2013.75 +/- 568.33 vs 1635.73 +/- 505.08 g; P=.005). The neonatal intensive care unit length of stay was significantly shorter in the RC group (23.17 +/- 19.24 vs 39.83 +/- 23.74 days; P=.004). The composite adverse neonatal outcome rate (50.00% vs 91.67%; aOR, 0.009; 95% CI, 0.074-0.72; P=.009), neonatal intensive care unit admission rate (50.00% vs 87.50%; aOR, 0.084; 95% CI, 0.008-0.88; P=.036) and usage rate of intubation or continuous positive airway pressure (58.33% vs 91.67%; aOR, 0.13; 95% CI, 0.02-0.81; P=.029) were significantly lower in the RC group than in the control group. CONCLUSION: RC in women with twin pregnancies with additional high -risk factors associated with preterm birth and cervical dilation after indicated cerclage placement might prolong gestation, decrease the rates of sPTB at <34 weeks' gestation and neonatal admission to the NICU, and improve perinatal and neonatal outcomes. To our knowledge, the present study is the first to investigate the effectiveness of RC compared with expectant treatment for twin pregnancies in women with cervical dilation after initial indicated cerclage placement. However, we acknowledge that this was a retrospective and single -institution investigation with a relatively small sample size. Further prospective investigations, including a multicenter, large cohort, are needed in the future.