Cervical Pessary for Preventing Preterm Birth in Singleton Pregnancies with Short Cervical Length: A Systematic Review and Meta-analysis

OBJECTIVES: To evaluate the effectiveness of cervical pessary for preventing spontaneous preterm birth (SPTB) in singleton gestations with a second trimester short cervix. METHODS: Electronic databases were searched from their inception until February 2016. We included randomized clinical trials (RCTs) comparing the use of the cervical pessary with expectant management in singletons pregnancies with transvaginal ultrasound cervical length (TVU CL) ≤25 mm. The primary outcome was incidence of SPTB <34 weeks. The summary measures were reported as relative risk (RR) with 95% confidence interval (CI). RESULTS: Three RCTs (n = 1,420) were included. The mean gestational age (GA) at randomization was approximately 22 weeks. The Arabin pessary was used as intervention in all three trials, and was removed by vaginal examination at approximately 37 weeks. Cervical pessary was not associated with prevention of SPTB <37 (20.2% vs 50.2%; RR 0.50, 95% CI 0.23 to 1.09), <34, <32, and <28 weeks, compared to no pessary. No differences were found in the mean of GA at, interval from randomization to delivery, incidence of preterm premature rupture of membranes and of cesarean delivery, and in neonatal outcomes. The Arabin pessary was associated with a significantly higher risk of vaginal discharge. CONCLUSIONS: In singleton pregnancies with a TVU CL ≤25mm at 200 -246 weeks, the Arabin pessary does not reduce the rate of spontaneous preterm delivery or improve perinatal outcome. Individual patient data meta-analysis may clarify whether cervical pessary may be beneficial in subgroups, such as only singleton gestations without prior SPTB or by different CL cutoffs.