10: Pessary to prevent preterm birth after an episode of threatened preterm labor (APOSTEL VI): a randomized controlled trial


      Women who are admitted for threatened preterm labor and who do not deliver, continue to have an increased risk for preterm birth (PTB). Neither treatment with progesterone nor maintenance tocolysis are effective in reducing the risk of PTB in these women. We assessed the effectiveness of a pessary to reduce the risk of PTB in a randomized controlled trial (RCT).

      Study Design

      We performed a multicenter open-label RCT in seven tertiary care centers in The Netherlands. Pregnant women between 24 and 34 weeks of gestation with threatened preterm labor with intact membranes, diagnosed through regular contractions with a cervical length (CL) less than 15 mm or a CL between 15 and 30 mm with a positive fetal fibronectin test result, were eligible when they remained undelivered for 48 hours and contractions had ceased. Women were randomized to a cervical pessary or no treatment (care as usual). Primary outcome was PTB <37 weeks. Secondary outcomes were composite adverse neonatal outcome, PTB <34 and PTB <32 weeks. To show a reduction in PTB <37 weeks from 40% to 20% (β 0.20, α 0.05), we planned to include 200 women with a singleton pregnancy.


      Between November 2013 and September 2016, 166 women (131 singletons, 35 twins) were randomized. At planned interim analysis, the independent DSMC advised to halt because the chance that the pessary would improve the primary outcome was futile, while there was one case of cervical rupture in the pessary group, and outside the trial several other cases of cervical rupture had been reported in women with contractions. The PTB <37 weeks rates were 48% in the pessary group versus 39% in the control group RR 1.2 (95%CI 0.83 to 1.8). Comparison of the secondary outcomes showed similar results (PTB <34 weeks RR 1.8 (95%CI 0.85 to 3.7) and PTB <32 weeks RR 2.0 (95%CI 0.78 to 5.0) and composite adverse perinatal outcome RR 1.2 (95%CI 0.49 to 2.9). These results were similar when we added twin pregnancies to the analysis.


      In women in whom contractions ceased after an episode of threatened preterm labor, a cervical pessary does not reduce the risk of PTB.
      Figure thumbnail fx1