Michael Beckmann1. 1. Department of Obstetrics and Gynaecology, Mater Health Service, Raymond Tce, South Brisbane, Queensland, Australia. michael.beckmann@mater.org.au
Abstract
BACKGROUND: A failed induction usually refers to failure to progress to the active phase of labour; however, there is no consensus regarding when an induction has failed. AIMS: To investigate the factors (particularly length of latent phase) that may influence mode of birth for women undergoing Syntocinon induction of labour. METHODS: A retrospective analysis of 978 nulliparous women undergoing Syntocinon induction of labour following artificial or spontaneous rupture of membranes was performed. RESULTS: As the length of the latent phase increased, the likelihood of birth by caesarean section increased significantly (P < 0.001). After ten hours of Syntocinon administration, the 8% of women not in the active phase of labour had approximately a 75% chance of being delivered by emergency caesarean section and after 12 h the chance was almost 90%. Multivariate analysis also suggested an association between birth by caesarean section and use of prostaglandin gel (P < 0.001) or mechanical methods of cervical priming (P = 0.004), maternal height < 155 cm (P = 0.020) and cervical dilation prior to commencement of Syntocinon (P = 0.018). CONCLUSIONS: It would seem reasonable to continue a Syntocinon infusion for at least ten hours in women undergoing induction who have yet to reach the active phase of labour ( 4 cm), and unclear benefit in continuing an induction beyond 12 h. The duration of latent phase is a helpful predictor of subsequent mode of birth.
BACKGROUND: A failed induction usually refers to failure to progress to the active phase of labour; however, there is no consensus regarding when an induction has failed. AIMS: To investigate the factors (particularly length of latent phase) that may influence mode of birth for women undergoing Syntocinon induction of labour. METHODS: A retrospective analysis of 978 nulliparous women undergoing Syntocinon induction of labour following artificial or spontaneous rupture of membranes was performed. RESULTS: As the length of the latent phase increased, the likelihood of birth by caesarean section increased significantly (P < 0.001). After ten hours of Syntocinon administration, the 8% of women not in the active phase of labour had approximately a 75% chance of being delivered by emergency caesarean section and after 12 h the chance was almost 90%. Multivariate analysis also suggested an association between birth by caesarean section and use of prostaglandin gel (P < 0.001) or mechanical methods of cervical priming (P = 0.004), maternal height < 155 cm (P = 0.020) and cervical dilation prior to commencement of Syntocinon (P = 0.018). CONCLUSIONS: It would seem reasonable to continue a Syntocinon infusion for at least ten hours in women undergoing induction who have yet to reach the active phase of labour ( 4 cm), and unclear benefit in continuing an induction beyond 12 h. The duration of latent phase is a helpful predictor of subsequent mode of birth.