Pregnant patients with increases in blood pressure are often treated with medication, in our view inappropriately. We examined 222 pregnant women who were referred because of two blood pressure determinations > 140/90 mm Hg. The women were primarily treated by nonpharmacological means. Only 44 required medications to maintain a blood pressure < 140/90 mm Hg. Twenty-six additional pregnant women referred for hypertension were taught to measure their blood pressures at home. Fourteen underwent 24-h ambulatory blood pressure monitoring. Home and 24-h blood pressure measurements were both significantly lower than those obtained in the office and did not significantly differ from each other. We conclude that most pregnant women without proteinuria, who show mild to moderate blood pressures > 140/90 mm Hg are best treated conservatively without drugs. Those in whom home or 24-h blood pressures exceed 140/90 mm Hg and who do not respond to nonpharmacologic methods require medication. Finally, "white coat" hypertension is common in pregnant women.