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

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 + 6weeks and at subsequent scheduled ultrasound scans prior to 28 weeks. Women with a TVS-CL of <= 30 mm at 18 + 0 to 27 + 6weeks were randomized to receive either the Bioteque (TM) 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 (C) 2017 ISUOG. Published by John Wiley & Sons Ltd.