Objectives: To describe the outcome of patients with twin-to-twin transfusion syndrome and cervical length≤25mm, treated with laser and an Arabin cervical pessary. Methods: Retrospective analysis of a consecutive series of all cases with severe twin-to-twin transfusion syndrome who underwent laser surgery: a group with cervical length above 25mm (group A) and two groups who had a cervical length of 25mm or less prior to the procedure. The first 8 cases (group B) were managed expectantly and the next 8 cases had a cervical pessary inserted immediately after laser surgery (group C). Gestational age at birth was the primary outcome. The secondary outcome was a composite one encompassing severe neonatal morbidity. Results: The median gestational age at laser surgery was 20weeks in all groups but the median gestational age at delivery was significantly higher in group C versus B (28 vs 32weeks, p=0.01). Severe neonatal morbidity was present in 18% in group C and 70% in group B (p<0.01). Conclusion: Early results suggest a potential role for pessary use in prolonging gestation in cases with shortened cervix at the time of laser. A randomized trial to test this hypothesis should be performed. © 2012 John Wiley & Sons, Ltd.