Comparison of two preparations of dinoprostone for pre-induction of labour in nulliparous women with very unfavourable cervical condition: a randomised clinical trial.

The aim of this study was to compare the clinical effects of preinduction cervical ripening by using two ways of dinoprostone administration. In a prospective, open-label trial, 144 consecutive nulliparous women with a Bishop score <4 who required induction of labour at term were randomised to receive dinoprostone via either a vaginal insert (10 mg over 12 h) or a cervical gel (0.5 mg, twice in 12 h). If labour did not start by 24 h after this preinduction, patients received 2 mg vaginal dinoprostone gel followed 6 h later by oxytocin infusion. The main outcome measure was the rate of caesarean sections (CS). Secondary measures were: changes in Bishop score at 6 h and 12 h, delivery within 12 h and 24 h, need for oxytocin for induction, failure of induction (delivery after >48 h), need for pharmacological interventions to manage tachysystole/hyperstimulation, length of stay in hospital. The CS rate was lower in the vaginal insert group (22.9%) than in the cervical gel group (34.3%), though the difference did not reach statistical significant difference (P = 0.13). The indications for CS overlapped between the groups. The rate of vaginal delivery within 12 h and 24 h was similar, as was the rate of failure of induction. More women in the gel group (41.4% versus 24.3%) required the use of oxytocin (OR = 2.21; 95% CI = 1.07-4.55). Tachysystole or hyperstimulation in the vaginal insert group (7) was twice that with cervical gel (4). Four women in the vaginal insert group and three in the cervical gel group reported infectious complications. A long stay in hospital (>4 days) was less frequent with vaginal inserts (21.4 versus 38.6%; OR = 0.43, 95% CI = 0.19-0.97). The more challenging preinductions of labour at term are associated with increased obstetric interventions such as a high CS rate and a more frequent requirement for oxytocin inductions. In terms of success and failure, vaginal inserts releasing dinoprostone do not differ from dinoprostone given by the traditional cervical route. However, the use of vaginal inserts reduces the need for obstetric interventions and allows shorter periods in hospital.