Efficacy of ultrasound-indicated cerclage in twin pregnancies

OBJECTIVE: We sought to compare the perinatal outcomes in twin pregnancies with short cervical length (CL) with ultrasound-indicated cerclage (UIC) vs no cerclage (control). STUDY DESIGN: This was a retrospective cohort study of asymptomatic twin pregnancies with transvaginal ultrasound (TVU) CL ≤25 mm at 16-24 weeks from 1995 through 2012 at 4 separate institutions. Exclusion criteria were: genetic or major fetal anomaly, multifetal reduction >14 weeks, monochorionic-monoamniotic placentation, or medically indicated preterm birth (PTB). Primary outcome was spontaneous PTB (SPTB) <34 weeks. Secondary outcome was SPTB <28, <32, and <37 weeks. We also planned to evaluate primary and secondary outcome for the subgroup of twin pregnancies with CL ≤15 mm. RESULTS: In all, 140 women with twin pregnancy and TVU-CL ≤25 mm were managed with either UIC (n = 57) or no cerclage (n = 83). Demographic characteristics were not significantly different except women who underwent UIC presented at an earlier gestational age (GA) at diagnosis of short CL. After adjusting for GA at presentation, there were no differences in GA at delivery or SPTB <28 weeks: 12 (21.2%) vs 20 (24.1%) (adjusted odds ratio [aOR], 0.3; 95% confidence interval [CI], 0.68-1.37), <32 weeks: 22 (38.6%) vs 36 (43.4%) aOR, 0.34; 95% CI, 0.1-1.13), or <34 weeks: 29 (50.9%) vs 53 (63.9%) (aOR, 0.37; 95% CI, 0.16-1.1). In the subgroup of women with CL ≤15 mm (32 with UIC and 39 controls) the interval between diagnosis to delivery was significantly prolonged by 12.5 ± 4.5 vs 8.8 ± 4.6 weeks (P < .001); SPTB <34 weeks was significantly decreased: 16 (50%) vs 31 (79.5%) (aOR, 0.51; 95% CI, 0.31-0.83) as was admission to neonatal intensive care unit: 38/58 (65.5%) vs 63/76 (82.9%) (aOR, 0.42; 95% CI, 0.24-0.81) when the UIC group was compared with the control group, respectively. CONCLUSION: UIC in asymptomatic twin pregnancies with TVU-CL ≤25 mm was not associated with significant effects on perinatal outcomes compared to controls. However, in the planned subgroup analysis of asymptomatic twin pregnancies with TVU-CL ≤15 mm before 24 weeks, UIC was associated with a significant prolongation of pregnancy by almost 4 more weeks, significantly decreased SPTB <34 weeks by 49%, and admission to neonatal intensive care unit by 58% compared with controls.