Objective: This study aimed to compare the efficacy of combined use of Arabin pessary, cervical cerclage and progesterone with progesterone-only management of pregnant women at high risk of preterm birth. Materials and methods: The study included 203 pregnant women at high risk of preterm birth who were randomised to receive Arabin pessary (Group 1, n = 82) and progesterone, circular cervical cerclage and progesterone (Group 2, n = 121) or progesterone treatment only (Group3, controls, n = 50). Patients in the pessary and cerclage group also received progesterone. Results: The use of Arabin pessary combined with progesterone resulted in a 2.5-fold decrease in the rate of vaginal dysbiosis in pregnancy (p = 0.015) and almost three-fold reduction in in the postpartum period (p = 0.037), combined with circular cervical cerclage and progesterone. Suture eruption was observed in 4.3% of women. In patients with abnormal placental location, placental migration was observed in 62.1% of patients in Group I, 52.1% in Group II and a significantly lower proportion of patients (14.0%) in Group III (p = 0.001). Bleeding during pregnancy was observed significantly more often in both comparison groups (p = 0.005). Incidence of intrapartum bleeding was 17.4% (p = 0.011) in Group II and 24.5% in Group III (p = 0.002). Intrapartum chorioamnionitis was observed in 4.3% of patients in Group II and 2.04% of patients in Group III. Conclusions: The use of Arabin pessary compbined with progesterone reduces the rate of infectious complications and bleeding during pregnancy and the postpartum period. © 2016 Informa UK Limited, trading as Taylor & Francis Group.