The purpose of this study is to evaluate the breathing patterns of women who undergo cesarean delivery with spinal or epidural morphine for post-operative pain control in the first day after surgery. Some women who undergo cesarean delivery may be at risk for respiratory complications related to opiate administration for post-operative pain. The primary aim of this study is to evaluate post-operative minute ventilation in women who undergo cesarean delivery using a novel method of non-invasive minute ventilation monitoring, and to see if there are predictive risk factors that may predispose women to post-operative hypoventilation.

Inclusion Criteria:

• 18 years or older
• planned cesarean delivery with neuraxial morphine for post-operative analgesia

Exclusion Criteria:

• Non-English speaking subjects
• patients who undergo urgent or emergent cesarean deliveries
• patients who receive general anesthesia or do not receive neuraxial morphine

Subjects will be pregnant woman recruited from the Duke Birthing Center (DBC) in the 5700 unit of Duke Hospital who are scheduled for planned cesarean delivery.