Mechanical versus pharmacological term induction: a cohort group analysis of maternal and neonatal outcome – hygroscopic cervical dilator versus intravaginal versus intracervical prostaglandin E2

Aim: To compare the efficacy & safety of hygroscopic cervical dilator versus two prostaglandin E2 application methods for term induction of labour.

Method: Above 36th weeks of gestation, all women, who were admitted to hospital for induction of labour, were labour induced either with the hygroscopic cervical dilator versus intravaginal 1 mg or intracervical 0.5 mg prostaglandin E2 irrespective of cervical Bishop score. The main outcome variables were induction-to-delivery interval, number of foetal blood samples, PDA rate, rate of oxytocin augmentation and rate of vaginal delivery.

Results: Sixty-three patients were enrolled in this study (Dilapan-S n = 26, intracervical n = 20, intravaginal n = 19). There were no differences between the three groups in respect to maternal age, gravity, parity, gestational diabetes, previous conisation of the cervix, previous caesarean section rate, reason for labour induction, gestational age and Bishop score. Outcome parameters showed that the induction-to-delivery was statistically significantly shorter in the intracervical compared to the Dilapan-S or the intravaginal group (median 12.8h (intracervical) versus 31.7h (Dilapan-S) or 29.9h (intravaginal); p = 0.03). No difference in induction-to-delivery time was found between Dilapan-S and intravaginal PGE2 (p > 0.05).

Summary: The intracervical PEG2 had the shortest induction-to-delivery time in comparison to intravaginal PEG2 and mechanical induction with Dilapan-S. With intracervical PEG2 high levels of uterine hyper stimulation (25%) were detected which all required pharmacological intervention with Ferenterol. Intravaginal PEG2 only rarely caused uterine hyper stimulation, whereas Dilapan-S showed no hyper stimulation at all.