Introduction: Induction of labour is one of the most common interventions in obstetrics, affecting nearly 25% of pregnancies in developed countries. The purpose of this study was to test the hypothesis that among multiparous women requiring cervical ripening as an initial step of induction, mechanical ripening with Foley catheter is more effective than prostaglandin preparations.
Methods: We performed a retrospective analysis of multiparous women with a singleton gestation who required cervical ripening in a single tertiary center (2014-2019). Women who underwent ripening with Foley catheter (Foley group) were compared to those who underwent ripening using controlled-release dinoprostone vaginal insert (PGE2-CR group) or dinoprostone vaginal gel (PGE2-gel group). The primary outcome was the ripening-to-delivery interval.
Results: A total of 229 women met the study criteria: 95 in the Foley group, 83 in the PGE2-CR group, and 51 in the PGE2-gel group. Women in the Foley group had a significantly shorter ripening-to-delivery interval compared with women in the PGE2-CR group (16.2±9.2 vs. 27.0±14.8 hours, p<0.001), and were more likely to deliver within 12 hours (47.4% vs. 12.0%, p<0.001; aRR 3.87, 95%-CI 2.07-7.26) and within 24 hours (78.9% vs. 49.4%, p<0.001; aRR 1.61, 95%-CI 1.26-2.06). Women in the Foley group were also less likely to require a second ripening method compared with women in the PGE2-CR group (1.1% vs. 8.4%, p=0.018; aRR 7.26, 95%-CI 2.99-17.62). These differences were not observed when comparing the Foley and the PGE2-gel groups. The cesarean section rate was similar between the Foley group (9.5%), PGE2-CR group (9.6%, p=0.970) and the PGE2-gel group (11.8%, p=0.664).
Conclusion: In multiparous women requiring cervical ripening, all methods of cervical ripening have a similar success rate. However, the use of PGE2-CR is associated with a considerably longer interval to delivery compared with Foley or PGE2-gel.
Liran Hiersch– MFM Fellow, Sunnybrook Health Sciences Centre, University of Toronto
Alexandra Moloney– Medical Student, Division of maternal fetal medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
Jasmine Idris Ali-Gami– Undergraduate Student, Division of maternal fetal medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
Anne Berndl– MFM Specialist, Sunnybrook Health Sciences Centre, University of Toronto
Elad Mei-Dan– MFM Specialist, North York General Hospital
Arthur Zaltz– Obstetrician, Sunnybrook Health Sciences Centre, Univeristy of Toronto
Jon Barrett– Chief of Maternal-Fetal Medicine at Sunnybrook Health Sciences Centre, Sunnybrook Health Sciences Centre, University of Toronto
Nir Melamed– MFM Specialist, Sunnybrook Health Sciences Centre, University of Toronto