The Arabin cervical pessary for the prevention of preterm birth in twin-to-twin transfusion syndrome treated by fetoscopic laser coagulation: a multicenter randomized controlled trial.

BACKGROUND: Miscarriage and preterm birth are leading causes of loss and disability in monochorionic twins following laser treatment for twin-twin transfusion syndrome.

OBJECTIVE: We investigated the use of the cervical pessary to reduce preterm birth before 32 weeks in monochorionic diamniotic twin pregnancies after fetal surgery for twin-twin transfusion syndrome.

STUDY DESIGN: In this open-label multicenter randomized trial pregnant women carrying monochorionic diamniotic twins requiring fetoscopic laser coagulation for twin-twin transfusion syndrome were randomly assigned in a 1:1 ratio to pessary placement or conservative management. The primary outcome was birth before 32 weeks. Secondary outcomes were birth before 28, 30, 34 or 37 weeks, preterm rupture of membranes, fetal and neonatal survival, and a composite of maternal and neonatal complications. The estimated sample size was 364 patients, with 182 cases in each arm of the study. The analysis was performed according to the intention-to-treat principle. Two interim analyses were planned.

RESULTS: The trial was stopped prematurely after the first planned interim analysis for futility. One hundred thirty-seven women were included in the analysis, 67 in the pessary and 70 in the conservative management group. A preterm birth before 32 weeks occurred in 27/67 women (40.3%) in the pessary group and in 25/70 women (35.7%) in the conservative management group (aOR, 1.19; 95%CI, 0.58-2.47, P=.63). No significant differences between groups were observed in the rate of deliveries before 28, 30, 34 and 37 weeks, respectively. Overall survival to delivery was 91.2% (125/137) for at least one twin and 70.8% (97/137) for both twins, with no differences between groups. Neonatal survival at 30 days was 76.5% (208/272). There were no differences between groups in maternal or neonatal morbidity.

CONCLUSION: In monochorionic diamniotic twin pregnancies requiring fetal therapy for twin-twin transfusion syndrome, routine use of cervical pessary did not reduce the rate of preterm delivery before 32 weeks.