6: Prevention of preterm birth with pessary in singletons (PoPPS): a randomized controlled trial


      To determine if pessary use prevents preterm birth (PTB) in singleton gestations with a short transvaginal ultrasound (TVU) cervical length (CL) and without a prior spontaneous PTB.

      Study Design

      Multicenter randomized controlled trial of asymptomatic women with singleton gestations with a TVU CL ≤ 25 mm at 180 - 236 weeks and no prior spontaneous PTB. Subjects were randomized to receive the Bioteque cup pessary or no pessary. Pessaries were inserted by MFM staff centrally trained in proper placement. Randomization was stratified by study site and CL(≤ 20 mm or >20-25mm). Treatment with vaginal progesterone was recommended to all women with a TVU CL ≤ 20 mm. Primary outcome was PTB<37 weeks. Composite adverse neonatal outcome included necrotizing enterocolitis, intraventricular hemorrhage (grade 3 or 4), respiratory distress syndrome, bronchopulmonary dysplasia, retinopathy, sepsis and neonatal death. Analysis was by intention-to-treat. Our required total sample size was 242. The trial was stopped prematurely by the DSMB due to the start of a competing NICHD MFMU pessary trial.


      A total of 17,388 women were screened with TVU CL; 446 (2.6%) had a TVU CL ≤ 25 mm. Of the 394 (88.3%) who met eligibility criteria, 122 (31.0%) consented to randomization. As of the time of submission, 111 women have delivered, 56 (92%) in the pessary and 55 (90%) in the no pessary groups. Demographic characteristics, mean gestational age (21 ± 1 week) and mean CL (16 ± 7 mm) at enrollment were similar in both groups. There were no significant differences between the pessary and no pessary groups in rates of PTB<37 weeks, PTB<34 weeks, PTB<28 weeks, gestational age at delivery, birth weight and composite neonatal outcome (Table).


      Our study showed that treatment with a cervical pessary did not prevent PTB in women with singleton gestations with a TVU CL ≤ 25 mm at 180 - 236 weeks and without a prior spontaneous PTB. Though study recruitment was stopped before we reached our enrollment goal, our findings are consistent with the recent studies that failed to show efficacy of pessaries in similar clinical settings.
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