Height \< 5'0"

Allergy to phenylephrine or ephedrine, or any other standardized medication

Severe Cardiac disease in pregnancy with marked functional limitations (NYHA Class III and IV)

Patients on Monoamine Oxidase Inhibitors or Tricyclic Antidepressants

History of recent amphetamine or cocaine use.

Subject enrollment in another study involving a study medication within 30 days of CD

Any other physical or psychiatric condition which may impair their ability to cooperate with study data collection

Phenylephrine Versus Ephedrine in Pre-eclampsia