Effects of preoperative sublingual misoprostol on uterine tone during isoflurane anesthesia for cesarean section

Background and objectives: Misoprostol would reduce the uterine bleeding after cesarean delivery without harmful effects on either mother or baby. We aimed to evaluate the effects of preoperative misoprostol on maternal blood loss, uterine tone, and the need for additional oxytocin after cesarean delivery under isoflurane anesthesia.

Methods: After ethical approval, 366 patients scheduled for elective cesarean delivery were randomly allocated to receive either sublingual misoprostol 400μg (n=179) or placebo tablet (n=187) after intubation. Anesthesia was maintained with 0.5-0.7 MAC isoflurane with nitrous oxide. All patients received intravenous infusion of 10IU of oxytocin after placental delivery. Perioperative estimated blood loss, uterine tone, need for supplementary oxytocin, hematocrit, Apgar scores at 1 and 5 min and adverse effects were recorded.

Results: After induction, patients receiving sublingual misoprostol had significant less perioperative estimated blood loss (202±383.1 vs. 708±204.3mL, p<0.001), need for oxytocin (p<0.001), higher hematocrit levels (p<0.001) and uterine tone (p<0.02). The incidence of shivering was higher in the misoprostol group (p=0.04). There were no differences between the two groups as regarding Apgar scores, nausea and vomiting, gastrointestinal disturbances and pyrexia.

Conclusion: Preoperative administration of sublingual misoprostol 400μg is safe and effective in attenuating the maternal bleeding and uterine atony from isoflurane anesthesia for cesarean delivery.