Plan to monitor central arterial pressure in women who are undergoing spinal anesthesia for cesarean delivery or epidural anesthesia for vaginal delivery.

Subjects will be screened as they are admitted to the maternity care floor (5th floor St. Mary's Hospital). Subjects will be approached if they are desiring regional anesthesia.

The subject will have an additional blood pressure cuff placed on the arm that anesthesia is not using for their blood pressure cuff. Central arterial pressure will be measured from the cuff:

• Prior to regional anesthesia placement
• Every 15 minutes for 1 hour
• Every 30 minutes for 2 hours Routine sphygmomanometer measurements will also completed at the above times. These are all study procedures.

Anesthesia will use their usual protocol for blood pressure monitoring and management during placement of, and after the procedure. No changes in patient management will be made based upon the central arterial pressure as the guidelines were developed with routine brachial pressure.

Inclusion Criteria:

• Singleton pregnancy
• Planned regional anesthesia

Exclusion Criteria:

• Multiple pregnancy
• Emergent cesarean delivery
• Irregular heart rhythms or arrhythmias
• Peripheral arterial disease, leg artery disease
• Reynaud's phenomena
• Intense cold/hypothermia
• If there is a wound at location of where central arterial cuff would be placed or tonometer for carotid assessment
• Severe tachycardia (>120)
• Greater than 1st degree heart block
• Congestive heart failure or heart disease
• Inability to adequately monitor BP
• Use of magnesium sulfate

Women who are admitted to our obstetrics ward and are planning on receiving regional anesthesia will be approached.