We hope that this pulse oximeter will provide important new information (SpHb) about hemoglobin measurement in patients undergoing elective CS, who may often experience significant blood loss and postpartum anemia in the perioperative period. The measurement of perioperative blood loss is often inaccurate, and formal measurements of hemoglobin levels are often associated with time delays, especially in the setting of ongoing acute blood loss. We hope that this device will provide accurate continuous data of hemoglobin in this patient population, which may prove to be a significant advance in patient monitoring in this patient population. Probes for SpHb measurement will be provided by Masimo Corporation.