Prophylactic Intravenous Calcium Gluconate to Decrease Blood Loss at Time of Cesarean Delivery in Pregnant Patients at High Risk for Uterine Atony

This research study is being done to learn what effect a single dose of calcium gluconate will have on blood loss at the time of cesarean delivery in pregnancy patients at high risk for uterine atony.

Inclusion Criteria: * English speaking * Viable Intrauterine Pregnancy, Gestational Age ≥24 weeks * Labor Converted to Cesarean Delivery at High Risk for Atonic Bleeding Defined as: Any exposure to oxytocin infusion for labor augmentation or induction prior to cesarean delivery * Or Scheduled Cesarean Delivery at High Risk for Atonic Bleeding Defined as scheduled Cesarean-Section (CS) plus any one of: 1. \> 4 Prior deliveries 2. General anesthesia 3. Multifetal gestation 4. Polyhydramnios diagnosed by ultrasound within 2 weeks 5. Macrosomia ≥ 4000gms; estimated fetal weight by palpation or by ultrasound 6. Fibroid uterus, defined as: Multiple ≥ 2cm intramural 7. Any history of prior Primary postpartum hemorrhage (PPH) 8. Platelets \< 100,000 (but \>50,000 9. Placenta Previa 10. Body Mass Index (BMI) ≥ 40 Exclusion Criteria: * Non-English speaking * Antenatal suspicion for placenta accreta spectrum * History of allergic reaction to Calcium Gluconate * Patients with hypertensive disorder of pregnancy receiving Magnesium Sulfate for seizure prophylaxis * Underlying Renal Disease defined as Cr\>1.0 * Known underlying cardiac condition * Cardiac glycosides (Digoxin) within two weeks for maternal or fetal indication * Treatment with a calcium channel blocker medication within 24 hours of screening * Hypertensive disorder necessitating intravenous antihypertensive medication within 24 hours of screening * Emergent case where study participation could impede care (judgement of obstetrician or anesthesiologist) * Known hypercalcemia * Concurrent use of any drugs that may cause hypercalcemia including 1. Vitamin D 2. Vitamin A 3. Thiazide Diuretics 4. Calcipotriene 5. Teriparatide * Ceftriaxone within 48 hours of screening * Total Parenteral Nutrition (TPN) within 48 hours of screening * Known Coagulopathy International Normalized Ratio (INR) ≥ 1.5 * Vaginal delivery