OC23.01: Cervical pessary to prevent preterm birth in twin pregnancies with a short cervix: RCT (PECEP‐twins). (September 2014) - Goya, M.M.; Rodo, C.; De la Calle, M.; Pratcorona, L.; Merced, C.; Llurba, E.; Higueras Sanz, T.; Muñoz, B.; Juan Clar, M.; Serrano, A.; Carreras, E.