A randomised clinical trial to determine the effect of beta-adrenergic blocking with propranolol on labour

Abstract

Background. Dysfunctional labour is a common problem, particularly in disadvantaged communities. Women who are anxious during labour have high adrenaline levels, which could lead to dysfunctional uterine contractions through beta-adrenergic receptor stimulation.

Objective. To determine whether beta-adrenergic blocking with propranolol would reduce the incidence of dysfunctional labour and decrease the caesarean section rate at Universitas and Pelonomi hospitals, Bloemfontein, South Africa.
Study design. A double-blind randomised controlled trial.

Methods. Women with prolonged labour during the active phase were randomised into receiving propranolol or a placebo. A standard protocol for managing labour was maintained, including pain relief and oxytocin infusion when necessary. Age, gravidity, parity, maternal weight, blood pressure and pulse rate before and 1 hour after administration of propranolol or placebo, amount of oxytocin given before and after randomisation, time and method of pain relief, time and method of delivery, Apgar score, fetal weight, indication for caesarean section, and any complications experienced were documented.

Results. Of the 53 women enrolled in the study, 25 received propranolol and 28 the placebo. There was no statistically significant difference between the two groups in number of caesarean sections performed (p=0.59). The only statistically significant difference was the number of cases in which oxytocin augmentation was used after randomisation. In the propranolol group, only 7 (28.0%) received oxytocin after propranolol was given, while in the placebo group 17 (60.7%) received oxytocin after the placebo was administered (p=0.03).

Conclusion. Beta-adrenergic blocking with propranolol did not reduce the caesarean section rate or the duration of labour in our population, but decreased the need for oxytocin.