This is a study of pregnant women undergoing a cesarean delivery. It will compare their
microcirculation before and after the anesthetic. Microcirculation means blood flow to the
extremely small blood vessels in the body. It will also look at the differences in
microcirculation of participants who receive an infusion of phenylephrine compared to
participants who don't. The investigators hypothesize that spinal anesthesia will reduce the
vascular density and proportion of perfused vessels.