Magnesium for Shivering in Epidural Lidocaine Deliveries

Eligibility Details: Inclusion Criteria: 1. Gestational age of ≥37 weeks 2. Women who are ≥ 19 years old 3. Women undergoing Cesarean delivery under lidocaine top-up via a preexisting epidural catheter inserted for labor analgesia 4. American Society of Anesthesiologist (ASA) Physical Status class 1 or 2 Exclusion Criteria: 1. Emergency Cesarean delivery with limited time for informed consent 2. Women who have received MgSO4 prior to study enrollment 3. Indication for alternative mode of anesthesia for Cesarean delivery (e.g., general anesthesia) 4. Medical conditions or medications that could lead to tremor or shivering. (e.g., movement disorder, untreated thyroid disease) or mask tremor or shivering (e.g., beta-blocker, benzodiazepine, anticonvulsants) 5. Active shivering at time of recruitment 6. Inability to read and understand English for the purpose of informed consent 7. Contraindications to receiving MgSO4 (hypersensitivity reactions, respiratory rate <16breaths/min, absent reflexes, urine output <100 mL during the previous 4 hours, renal failure, or hypocalcemia) 8. History of previous postpartum hemorrhage