Effect of Melatonin on Blood Loss After Cesarean Section: A Prospective Randomized Double-Blind Trial

Background and Objectives The similarities between the melatonin and oxytocin signaling could lead to increased contractility of myometrium. We designed this randomized double-blind, placebo-controlled trial to evaluate the efficacy of melatonin in reduction of blood loss during and after the lower segment cesarean section. Methods One hundred and twenty patients who had been scheduled for cesarean section under spinal anesthesia were enrolled in the study. We randomly allocated them to one of the three following groups to receive either melatonin 3 mg (M-3), melatonin 6 mg (M-6), or placebo (P) sublingually 20 min before the surgery. The hemoglobin levels before and 12 h after surgery, the mean weight of the materials used in the operation time, the need for additional oxytocic therapy, and the incidence of adverse effects were probed and recorded. Results There was a significant difference between the group M-6 and both M-3 and P in the mean weight of the materials (p = .024 and .041, respectively) and between M-6 and P groups in terms of mean decrease in hemoglobin during 12 h after cesarean section (p = .029). Conclusion Using 6 mg melatonin, sublingually, as a premedication in patients undergoing cesarean section with spinal anesthesia could statistically reduce the amount of blood loss after the lower segment cesarean section, although it may not be clinically meaningful. Registration number: ACTRN12612000117819 and ClinicalTrials.gov Identifier: NCT01572805