Background: The purpose of the present study is the comparison between the effect of oxytocin alone or in combination with propranolol on the labor.

Materials & Methods : A double blind randomized controlled trial was performed on 150 nuliparas with gestational age of 39-41 weeks of pregnancy and Bishop score of ≤5, singleton, and cephalic presentation. The patients were randomly assigned in two groups. In the first group (oxytocin group=75), oxytocin was started at the rate of 2 mIu/ml and increased to a dose of 2 mIu/ml every 15 minutes until desired contractions were obtained Then it was continued at this rate for 8 hours. If the patients entered the active phase of labor, induction would be continued until delivery otherwise, the induction would be discontinued and patients would be transferred to the pre-labor ward, and on the next day, the protocol was performed again, unless patients were entered the active phase and deliver, cesarean would be performed. In the second group (propranolol group=75 cases), before the beginning of oxytoicn, 2mg propranolol was slowly injected intravenously then the oxytocin was initiated similar to the previous group and, in the second day of induction, before beginning of oxytocin, a 2mg propranolol was injected intravenously again and inductions were performed completely like the other group.

Results: There were no statistically significant difference between the two groups according to maternal and gestational age, primary Bishop score and neonatal birth weight. The number of patients who delivered at the first day did not show statistically significant difference between the two groups. [54 (72%) patients in Oxytocin group vs 62(82.6%) patients in propranolol group]. The mean duration for obtaining good contractions was shorter in propranolol group in the both first and second day of induction (2.59±0.87 h vs 3.7±2 h, p=0.000 for the first day and 1.8±1 h vs 3.9±0.89 h, p<0.002 for the second day). The mean interval between the beginning of induction until the beginning of active phase (3-4 cm dilatation of cervix) at the first day of induction was significantly shorter in propranolol group (3.6±1.6 h vs 5.6±2.4 h, p=0.000). The mean interval between the beginning of induction until delivery at the first day of induction was significantly shorter in propranolol group (7.67±2.5 h vs 10.18±4.1 h, p=0.000). The amount of necessary oxytocin for the first day of induction was less in propranolol group (14372.8±8209 mIu vs 11362±4013 mIu, p<0.005). The other variables did not show statistically significant difference between the two groups according to the neonatal Apgar scores of minute 1 and 5. The cesarean rate in oxytocin only group was 9 cases (12%) and in propranolol group was 7 cases (9.2%), without any significant difference.

Conclusion: Propranolol may shorten the induction duration and labor and reduce the amount of necessary oxytocin.