Prevention of preterm birth with pessary in twins (PoPPT): a randomized controlled trial

ABSTRACT Objective To evaluate whether cervical pessary placement prevents preterm birth ( PTB ) in twin gestations with a short mid‐trimester cervical length ( CL ) on transvaginal sonography ( TVS ). Methods This was a multicenter randomized controlled trial of asymptomatic women with a twin gestation and a TVS‐CL of ≤ 30 mm at 18 + 0 to 27 + 6 weeks' gestation. TVS‐CL was measured at the time of the fetal anatomy scan at 18 + 0 to 23 + 6 weeks and at subsequent scheduled ultrasound scans prior to 28 weeks. Women with a TVS‐CL of ≤ 30 mm at 18 + 0 to 27 + 6 weeks were randomized to receive either the Bioteque™ cup cervical pessary or no pessary. Randomization was stratified by gestational age, study site and chorionicity. Women with a monoamniotic twin gestation, twin–twin transfusion syndrome, early selective intrauterine growth restriction or placenta previa were excluded. Cervical pessaries were inserted by maternal‐fetal medicine staff centrally trained in proper placement. No other treatment for women with a short cervix was recommended. Primary outcome was PTB < 34 weeks. The trial was stopped early before complete enrollment. Results A total of 421 women with a twin gestation were screened for TVS‐CL , and 85 (20%) had a TVS‐CL of ≤ 30 mm. Of these, 80 (94%) met the eligibility criteria and 46 (58%) of the eligible women agreed to randomization. Twenty‐three (50%) women were randomized to pessary placement and 23 (50%) to no pessary. Demographic characteristics, including median gestational age (21.0 vs 21.2 weeks; P = 0.69) and TVS‐CL (16.7 vs 22.9 mm; P = 0.45) at randomization, were similar between the pessary and no‐pessary groups, except for level of education (more than high school education: 48% vs 78%, respectively; P = 0.03) and proportion of spontaneous conceptions (83% vs 43%, respectively; P = 0.01). There were no significant differences between the pessary and no‐pessary groups in rate of primary outcome, PTB < 34 weeks (39% vs 35%; relative risk, 1.13 (95% CI , 0.53–2.40)), as well as other outcomes, including PTB < 37 weeks and < 28 weeks, gestational age at delivery, birth weight and composite adverse neonatal outcome. Conclusion Treatment with cervical pessary was not associated with the prevention of PTB in women with a twin gestation and a mid‐trimester TVS‐CL of ≤ 30 mm in this small underpowered randomized controlled trial. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.