This report updates the 1990 "National High Blood Pressure Education Program Working Group Report on High Blood Pressure in Pregnancy" and focuses on classification, pathophysiologic features, and management of the hypertensive disorders of pregnancy. Through a combination of evidence-based medicine and consensus this report updates contemporary approaches to hypertension control during pregnancy by expanding on recommendations made in "The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure." The recommendations to use Korotkoff phase V for determination of diastolic pressure and to eliminate edema as a criterion for diagnosing preeclampsia are discussed. In addition, the use as a diagnostic criterion of blood pressure increases of 30 mm Hg systolic or 15 mm Hg diastolic with blood pressure <140/90 mm Hg has not been recommended, because available evidence shows that women with blood pressures fitting this description are not more likely to have adverse outcomes. Management distinctions are made between chronic hypertension that is present before pregnancy and hypertension that occurs as part of the pregnancy-specific condition of preeclampsia, as well as management considerations for women with comorbid conditions. A discussion of the pharmacologic treatment of hypertension during pregnancy includes recommendations for specific agents. The use of low-dose aspirin, calcium, or other dietary supplements in the prevention of preeclampsia is described, and expanded sections on counseling women for future pregnancies and recommendations for future research are included.