A randomized controlled trial of Dilapan-S vs Foley balloon for preinduction cervical ripening (DILAFOL trial)

Antonio Saad, Josephine Villarreal, Joe Eid, Nicholas Spencer, Viviana Ellis, Gary Hankins, George Saade

Research output: Contribution to journalArticle

5 Scopus citations


Objective: The objective of the study was to test the hypothesis that Dilapan-S is not inferior to the Foley balloon for preinduction cervical ripening at term. Study Design: Pregnant women ≥37 weeks scheduled for induction with unfavorable cervix (≤3 cm dilated and ≤60% effaced) were randomly assigned to 12 hours of either Foley balloon inflated with 60 mL saline or Dilapan-S for cervical ripening. If the cervix remained unfavorable, then 1 more round of the assigned dilator was used. Management following ripening was left up to the clinical providers. The primary outcome was vaginal delivery. A satisfaction survey was also obtained after the preinduction period. Sample size was based on a noninferiority margin of 10%, 90% power, and an estimated frequency of vaginal delivery of 71% in Foley balloon and 76% in Dilapan-S. Results: From November 2016 through February 2018, 419 women were randomized (209 to Foley balloon; 210 to Dilapan-S). In the intent-to-treat analysis, vaginal delivery was more common in Dilapan-S vs Foley balloon (81.3% vs 76.1%), with an absolute difference with respect to the Foley balloon of 5.2% (95% confidence interval, –2.7% to 13.0%) indicating noninferiority for the prespecified margin. The difference was not large enough to show superiority. Noninferiority was confirmed in the per-protocol population (n = 204 in the Foley balloon, n = 188 in Dilapan-S), supporting the robustness of the results. Secondary outcomes were not different between groups, except for a longer time the device remained in place in Dilapan-S compared with the Foley balloon. Maternal and neonatal adverse events were not significantly different between groups. A priori interaction analyses showed no difference in the effect on vaginal delivery by cervical dilation at randomization, parity, or body mass index >30 kg/m 2 . Patients with Dilapan-S were more satisfied than patients with the Foley balloon as far as sleep (P =.01), relaxing time (P =.001), and performance of desired daily activities (P =.001). Conclusion: Dilapan-S is not inferior to the Foley balloon for preinduction cervical ripening at term. Advantages of Dilapan-S over Foley include Food and Drug Administration approval, safe profile, no protrusion from the introitus, no need to keep under tension, and better patient satisfaction.

Original languageEnglish (US)
Pages (from-to)275.e1-275.e9
JournalAmerican journal of obstetrics and gynecology
Issue number3
StatePublished - Mar 1 2019



  • cervical ripening
  • Dilapan-S
  • induction
  • labor
  • mechanical

ASJC Scopus subject areas

  • Obstetrics and Gynecology

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