[Hypertensive disorders in pregnancy]

Abstract

Background: Hypertensive complications contribute to maternal and fetal morbidity. Hypertensive diseases in pregnancy comprise various disorder from transient hypertension to the dangerous preeclampsia/eclampsia. Diagnosis of these diseases requires an understanding of the normal physiological adaptations during pregnancy.

Pathogenesis: The primary cause of preeclampsia/eclampsia is a disturbed growth of throphoblast cells, probably induced by an altered maternal immunotolerance. The consequence is a dysfunction of endothelial cells with a decrease in perfusion of the uterus and placenta. The normal balance between vasoconstrictors and vasodilators is changed in favor of vasoconstrictors. Complex changes in the renin-angiotensin system have been detected resulting in an increased angiotensin II-mediated vasoconstriction. The reduction in perfusion of the uterus and placenta eventually leads to preeclampsia/eclampsia and growth retardation of the fetus. Manifest preeclampsia/eclampsia is characterized by disturbed microcirculation of target organs such as brain, liver and kidney. An involvement of the liver causes the HELLP syndrome.

Therapy: Various pharmacological approaches to prevent preeclampsia/eclampsia showed disappointing results, but patients with a risk for the eventual development of preeclampsia/eclampsia should be identified, closely monitored, and hypertension should be treated. A systolic blood pressure > 170 mm Hg and diastolic blood pressure > 100 mm Hg should be treated. Drugs such as alpha-methyldopa and dihydralazine that are well-characterized in their fetal effects are the primary choice for the treatment of hypertension in pregnancy. ACE-inhibitors and angiotensin II receptor antagonists are absolutely, diuretics are relatively contraindicated. The causal therapy for preeclampsia/eclampsia is delivery. Gravida before the 33th week of pregnancy should be admitted, hypertension should be treated, and the fetus should be monitored by duplex ultrasound and cardiotocography. New data suggest that early treatment with glucocorticoids may prevent the manifestation of HELLP syndrome. Hypertensive pregnant patients should be treated in tertiary centers with an interdisciplinary approach involving obstetricians, neonatologists, and nephrologists.