Effect of Intramuscular Hyoscine N-Butyl Bromide on the Duration of the First stage of Labour in Nulliparous Women: A Randomized, Double-blind, Placebo-controlled Trial

Abstract

Background: Prolonged labour is common among nulliparous women and is associated with significant adverse feto-maternal outcomes. The complications associated with oxytocin-augmented labours have led to the search for other agents that can aid in shortening the duration of the first stage of labour without serious side effects. Previous studies have demonstrated that antispasmodics influence the course of labour. Aim: To evaluate the effect of intramuscular HBB on the duration of the first stage of labour in nulliparous women. Materials and Method: This was a randomized, double-blind, placebo-controlled study involving 136 nulliparous women presenting in spontaneous labour at Wuse District Hospital Abuja. They were randomized to receive either a single intramuscular 20mg of HBB or 1mL of distilled water, on diagnosis of active phase of labour. The mean durations of the three stages of labour and maternal drug side effects were compared between the two groups. Data analysis was on an intention-to-treat, using Statistical Package for Social Sciences (SPSS) version 26. The level of statistical significance was set at P< 0.05 at a confidence interval of 95%. Results: The mean duration of the first stage of labour was significantly shorter in the HBB group than in the control group (321.6 ± 20.50 min vs 381.7 ± 27.59 min, P=0.02; mean difference of 60.1 minutes). There were no statistically significant differences in the duration of the second and third stages of labour, maternal drug side effects and neonatal outcomes. Conclusion: Hyoscine butyl bromide was found to be safe and effective in shortening the duration of the first stage of labour in nulliparous women.

Key Words: Hyoscine butyl bromide, nulliparous, first stage of labour, duration of labour.