Effect of Hyoscine Butyl Bromide on the Duration of First Stage of Labour at a Tertiary Health Facility in Southern Nigeria

Background: The quest for techniques that shorten and thus reduce the discomfort of labour processes without associated maternal or fetal adverse effects is still on-going. Hyoscine-N-butyl bromide (HBB) has been in use in contemporary obstetric practice but reports supporting its efficacy in reducing the duration of labour are still incongruous. Aim: To determine the effect of intravenous hyoscine-N-butyl bromide on the duration of first stage of labour in nulliparous women at the University of Port-Harcourt Teaching Hospital. Material and Methods: This was a randomized controlled double blind equivalence clinical trial, involving 128 parturients, who presented to the labour ward of the University of Port Harcourt Teaching Hospital at term and received an intravenous injection of either 20 mg of HBB or normal saline once active stage of labour (5 cm) was established. Data analysis was with SPSS version 28 using inferential statistics. Results: There was no significant difference in the mean duration of active stage of labour. The HBB group demonstrated a mean dilatation rate of 1.01 ± 0.1 cm/hour, whereas the placebo group showed a marginally higher rate of 1.03 ± 0.1 cm/hour (p = 0.4). The HBB group had a mean duration of 19.5 ± 5.1 minutes during the second stage of labour, compared to 19.5 ± 6.0 minutes in the placebo group (p = 1.0). However, the HBB group showed a significant (p = 0.04) increase in the fetal heart rate (143.4 ± 7.2 bpm), while the placebo group experienced a slight decrease (140.6 ± 7.9 bpm). Conclusion: The duration of the active phase of labour was not shortened by hyoscine butyl bromide. In addition, the feto-maternal outcomes remained unchanged. However, HBB slightly increased the fetal heart rate.