Cerclage pessary containing progesterone homogeneously distributed in thepessary body providing a prolonged, sustained and continuous release for aperiodof at least 6 months, wherein the pessary consists of dimethylsiloxaneelastomerwith RTV (Room Temperature Vulcanization) mechanism, the progesteroneamount is from 20% to 30% w/w, relative to pessary weight and the ratios ofthepolymers forming the matrix is from 6:1 to 14 1. The cerclage pessary isuseful forthe prevention of preterm birth. Progesterone diffuses through the polymercontinuously, without altering the shape and integrity of the pessary, sincetheelastomer forming the polymeric matrix used herein is not biodegradable. Thisguarantees that the form of pessary remains intact until the end of treatment
