Diagnosis and management of chronic hypertension in pregnancy.

Pregnancies complicated by chronic hypertension are at increased risk for the development of superimposed preeclampsia, abruptio placentae, and poor perinatal outcome. The frequency of these complications is particularly increased in patients with severe hypertension and those with preexisting cardiovascular and renal disease. Such women should receive appropriate antihypertensive therapy and frequent evaluations of maternal and fetal well-being. In contrast, in patients with mild essential chronic hypertension, the maternal and perinatal benefits from antihypertensive medications are highly controversial. A review of the literature revealed two placebo-controlled studies, four trials comparing treatment versus no medication, and three comparisons of methyldopa and oxprenolol. In only one of these studies were subjects randomized in the first trimester. No differences in pregnancy outcome were found with the use of antihypertensive drugs. Evaluation of the woman with chronic hypertension who is considering pregnancy should begin before conception to establish the cause and severity of the hypertension. Appropriate management should include frequent evaluation of maternal and fetal well-being; antihypertensive medications may be useful in patients with severe disease as well as in those with target organ involvement.