The Efficacy of Intravenous Hyoscine-N-Butylbromide Buscopan® for the Acceleration of Labour in First Time Parturients: A Randomised, Double-Blind, Placebo-Controlled Trial

Objective: to establish the safety and efficacy of hyoscine-N-butylbromide (Buscopan®) in accelerating labour in first time parturients. Design: a randomised, double-blinded, placebo-controlled clinical trial. Setting: the antenatal clinic and maternity unit of the Aga Khan University Hospital Nairobi, Kenya. Population: first time parturients in spontaneous labour at term. Methods: women were randomised to receive 40mg of hyoscine-N-butylbromide or sterile water for injection intravenously once they were confirmed to be in active labour. The dose could be repeated once after four hours. Outcome measures: the main outcome measure was the duration of labour from diagnosis of active stage to delivery. Secondary outcome measures were rate of cervical dilatation and postpartum satisfaction score. Safety aspects such as drug adverse effects, APGAR scores and postpartum hemorrhage were explored. Results: a total of 85 were randomised and 79 yielded data for analysis. Of these 37 received hyoscine-N-butylbromide and 42 received placebo. There was no significant difference in the mean duration of active labour to second stage between the drug and placebo arms (396.2 versus 389.3 minutes, respectively, p=0.881, 95% CI -85.9 to 99.8). The mean rate of cervical dilatation in the drug arm was 1.17 centimetres per hour (cm/hr) compared to 1.22cm/hr in the placebo arm. This difference was not statistically significant (p value=0.832, 95% CI -0.5 to 0.4). The postpartum satisfaction scores were similar between the two arms. Hyoscine-N-butylbromide was well tolerated without any major adverse effects observed in either arm. Conclusion: hyoscine-N-butylbromide does not shorten the duration of labour in first time parturients in spontaneous labour. It also does not change maternal satisfaction with care received and is not associated with major adverse outcomes in the mother or newborn.