Objective: To compare oxytocin infusion alone and with intravenous (i.v.) propranolol in the management of dysfunctional labor.
Methods: Ninety-six parturients with abnormalities of the active phase of labor were randomly assigned to either propranolol 2 mg IV or an identical placebo, in addition to continuous infusion of oxytocin. Administration of propranolol or placebo was repeated in 1 hour if there was no change in cervical dilation. Patients not responding to this second administration of propranolol or placebo were delivered by cesarean.
Results: Among 96 subjects enrolled, 49 were allocated to the propranolol group and 47 to the placebo group; 13 (26.5%) of the former were delivered by cesarean, compared with 24 (51.1%) of the latter (relative risk 0.58, 95% confidence interval 0.35-0.93; P = .02). Between the two groups, no differences were observed in low Apgar scores, cord arterial pH, or incidence of admissions to the neonatal intensive care nursery. Maternal morbidity was similar in both groups. After logistic regression analysis controlling for nulliparity, birth weight, and epidural anesthetic use, the significant reduction in the cesarean rate associated with use of propranolol persisted. Propranolol administration was associated with a markedly reduced cesarean rate among patients with inadequate uterine contractility.
Conclusion: Low-dose administration of IV propranolol in patients with dysfunctional labor augmented with oxytocin safely reduced the need for cesarean delivery, particularly among patients with inadequate uterine contractility.