Methods/Design: This is an open-label, pilot, multicentre, prospective, randomised controlled trial (RCT). Enrolees are women with singleton pregnancies and previous PB based on CI (primary intervention, <16 weeks) or in case of previous PB and a short cervical length in current pregnancy ≤ 25 mm (secondary intervention, <24 weeks). Women are randomised (1:1) either to cervical cerclage or pessary treatment. The primary outcome is the spontaneous preterm birth rate before 34 weeks of gestation. The sample size was calculated, as a pilot study, based on the estimated population that we will be able to recruit during the duration of the trial: 60 women, 30 for each group (cervical cerclage and cervical pessary group) to observe, at least a reduction in the PB rate < 34 weeks from 34% to 27% in the pessary group, as does cerclage.