All centers in the United States that choose to prescribe an antihypertensive medication for use in pregnancy do so by trial and error, whereas impedance cardiography can help the clinician choose the best medication from the start. Many pregnant patient patients have chronic hypertension and this population is at increased risk for superimposed preeclampsia and other pregnancy complications. The current recommendation for pregnancy is to NOT treat mild hypertension because studies have not shown any benefit. These studies, have also not shown any harm. Prior studies that have shown no benefit to treatment of mild hypertension in pregnancy may be hampered by choosing the wrong antihypertensive medication, thereby not improving the rate of superimposed preeclampsia and other pregnancy related complications.