Impact of Preoperative Cervical Length on Pregnancy Outcome in Twin-Twin Transfusion Syndrome

Objective To evaluate the impact of preoperative cervical length on pregnancy outcome in monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome that underwent laser surgery or cord occlusion. Materials and Methods Retrospective study of 330 patients stratified by preoperative cervical length (>= 25 mm, 16-24 mm,<= 15 mm). Maternal characteristics, operative data, and pregnancy outcomes were compared between the cervical length groups as well as between the subgroups of patients with a cervical length <= 15 mm according to management (expectant vs. cerclage). Results A preoperative cervical length >= 25 mm was observed in 82% (n=271) of cases, 16-24 mm in 9% (n=29), and <= 15 mm in 9% (n=30). Patients with a preoperative cervical length <= 15 mm showed shorter median procedure-to-delivery interval (5.5 weeks vs. 11.6 (16-24 mm) vs. 13.0 (>= 25 mm); p<0.001); lower median gestational age at delivery (29.5 weeks vs. 34.3 (16-24 mm) vs. 33.4 (>= 25 mm); p<0.001); higher rate of preterm delivery<32 weeks (78 vs. 20% (16-24 mm) vs. 31% (>= 25 mm); p<0.001); and lower neonatal survival rate of at least one twin (70 vs. 88% (16-24 mm) vs. 93% (>= 25 mm); p<0.001). Outcome of patients with a preoperative cervical length <= 15 mm was similar regardless of management. Conclusion Monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome with a preoperative cervical length <= 15 mm showed a higher rate of preterm delivery<32 weeks and lower neonatal survival. The role of a cervical cerclage remains unclear.