Treatment of hypertension in pregnancy.

A better understanding of the hemodynamic abnormalities in gestational hypertension together with the use of effective antihypertensive agents have resulted in more rational therapeutic approaches and a substantial improvement in maternal and fetal welfare. In normal pregnancy, there is reduced vascular reactivity with peripheral pooling and decreased circulatory responses to pressor agents. These are prostacyclin-dependent processes. In gestational hypertension, the normal increase in plasma volume and cardiac output with pregnancy is attenuated and prostacyclin-dependent processes are impaired, resulting in persistent vasoconstriction, enhanced responses to pressor agonists, and failure to develop adequate uteroplacental interchange. Among the modern antihypertensive agents, alpha- and beta-adrenergic antagonists and calcium ion entry blockers have permitted safe and effective long-term blood pressure control with sustained fetal growth. The development of proteinuria that can occur in chronic hypertension or in previously normotensive women (toxemia of pregnancy) can be prevented by the use of beta-adrenergic blocking agents and possibly by low-dose aspirin (75 mg/day). Maternal prostacyclin-thromboxane imbalance, important in the pathogenesis of gestational hypertension, is corrected by low-dose aspirin treatment. With the prevention of pre-eclampsia, the adverse maternal and fetal prognosis in gestational hypertension has been improved.