Comparison of our results to related studies
dysfunction of labor, Pergialiotis, anxiety, labor pains
POSTPARTUM HEMORRHAGE, CONTRACTIONS, SECONDARY, DYSFUNCTIONAL LABOR, COMPLICATIONS
Different studies handled propranolol in different aspects of labor beginning early with dysfunction of labor, induction of labor by IV propranolol with oxytocin, the active stage of labor with oxytocin, oral propranolol, and oxytocin with induction, a recent study only with misoprostol but with IV propranolol, our study compares oral propranolol and vaginal misoprostol in labor induction.The first uncontrolled trial studying the effect of propranolol on dysfunctional labor was conducted in 1975 by Mitrani and colleagues. IV propranolol was administered to ten primigravidae with dysfunctional labor. This was followed by normal uterine activity and delivery without significant maternal or fetal complications. They assumed that labor pains were accompanied by fear and anxiety due to the release of catecholamines, which activated beta-adrenergic receptors causing weak uterine contractions [In the study of Sanchez-Ramos et al., 1999 regarding parturients with dysfunctional labor, ninety-six parturients were randomized during the active stage of labor to propranolol 2 mg IV versus placebo with continuous oxytocin infusion. Their results showed significant improvement in uterine contractility and a subsequent decrease in CS rates [The effect of IV propranolol/oxytocin in labor induction vs. placebo/oxytocin was handled in several studies. In the double-blind randomized controlled trial of Kashanian et al., 2008, 150 nulliparas parturients were randomized into 2 groups. In the first group oxytocin alone was used for the induction of labor. In the second group, 2 mg propranolol was slowly injected intravenously then the oxytocin was initiated. In agreement with our study, their results showed a shorter induction delivery time and shorter latent phase of labor. Contrary to our study, the amount of necessary oxytocin used was significantly less in the propranolol group [In agreement with our study is the meta-analysis by Pergialiotis et al. 2016 on the effect of adding propranolol with oxytocin during the latent and active phases of labor. They enrolled 609 parturients from 6 studies. They concluded that there is evidence supporting that propranolol shortens the latent phase, possibly the Induction-delivery time, and has no effect in decreasing the active stage of labor. Contrary to our study, they concluded that propranolol effectively lowered the cesarean section rates (OR 0.49, 95% CI 0.27, 0.89). This meta-analysis also showed no difference in the 5 min neonatal Apgar scores and NICU admissions, which agrees with the present study [Oral Propranolol was used in the study of Moghadam et al., 2013 in which 146 nulliparous women undergoing labor induction were randomized into 2 groups; the first group used propranolol administered orally in a dose of 20 mg then introduced oxytocin, and the second group placebo was taken before oxytocin. In agreement with our results, they showed a significantly shorter induction-delivery time and shorter latent phase of labor. Contrary to our study, they found significantly lower cesarean section rates in the propranolol group [The study of Bigelow et al., published in 2020, was the same as our study design; it was a single-blind, randomized, placebo-controlled trial of Primigravidae patients undergoing labor induction either. Two hundred and Forty Patients were randomized to receive 2 mg of IV propranolol or saline placebo before induction by 30 min. There were 240 patients enrolled in this study with 121 patients randomized to propranolol and 119 to placebo. About 64.2% of patients (154) delivered vaginally. There was no statistically significant difference in the induction-delivery time as a primary outcome. There was no statistically significant difference in the secondary outcomes (in cesarean section rate, time to active labor, or time to full dilatation in patients receiving propranolol vs. placebo. Interestingly they found a significantly lower rate of composite maternal morbidity in the propranolol group with lower rates of postpartum hemorrhage and transfusion [The discrepancies between our results and the results of previous studies may be attributed to the fact that we used misoprostol for induction of labor, unlike all the other studies, and that we used oral propranolol which has a longer lasting half-life compared to the intravenous propranolol used in most of the previous studies. Despite all the discrepancies, propranolol has been shown to affect myometrial contractility and the course of labor with no significant neonatal effects.