Background
Cervidil® (dinoprostone) intravaginal pessaries are used for induction of labour and maintain serum prostaglandin levels for up to 24 h. The Therapeutic Goods Administration approves Cervidil® for 12‐h use. However, twenty‐four‐hour use of Cervidil® is supported in Europe, New Zealand, America and some Australian hospitals.

Aim
To assess the safety of Cervidil® use for up to 24 h for induction of labour in nulliparous women.

Methods
A retrospective cohort study of 269 consecutive women receiving Cervidil® at the Royal Brisbane and Women’s Hospital (RBWH) between July 2007 and December 2008 was performed. The primary outcome measures were frequency of, and time to, uterine tachysystole with or without fetal heart rate (FHR) changes. Secondary outcome measures included frequency of maternal (intrapartum temperature, postpartum haemorrhage) and neonatal (low Apgars, resuscitation, nursery admission) morbidity. Morbidity outcomes of those who received Cervidil® for less than or equal to 12 h were compared with those who received Cervidil® for more than 12 h.

Results
Uterine tachysystole occurred in 9.3% of patients receiving Cervidil®, with a mean time to tachysystole of 10 h. The majority of cases (68%) occurred within 12 h of use. There was no increase in maternal or neonatal morbidity for those who received Cervidil® for longer than 12 h.

Conclusion
Twenty‐four‐hour use of Cervidil® is likely as safe as 12‐h use for induction of labour in nulliparous women.