[Hypertensive disorders in pregnancy]

Abstract

Hypertension in pregnancy is defined by a systolic blood pressure > or = 140 mm Hg and a diastolic blood pressure of > or = 90 mm Hg or by a rise in blood pressure of systolic > or = 30 mm Hg and diastolic > or = 15 mm Hg. High blood pressures are found in 5-10% of all pregnancies. The outcome of pregnancy is influenced by the fact whether there occurs a proteinuria in addition to hypertension. While the prognosis of an isolated hypotension is good, the combination of hypertension and proteinuria leading to preeclampsia is the primary cause of maternal death in many countries and is responsible for 20-25% of perinatal mortality. A simple classification divides between chronic hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension and transient hypertension. With chronic hypertension pregnancy outcome is determined by a preexisting nephropathy and the occurrence of a superimposed preeclampsia. Preeclampsia and superimposed preeclampsia are pregnancy induced multiorganic diseases, endangering both the mother and the fetus. Transient hypertension is a benign pathology, which occurs toward the end of pregnancy usually on the basis of a latent essential hypertension, which is laid open through pregnancy. While a severe chronic hypertension in pregnancy must be treated to prevent a hypertensive maternal encephalopathy, a less severe chronic hypertension should not be treated as the risk of a superimposed preeclampsia and the maternal and fetal outcome cannot be influenced by antihypertensive therapy. The incidence of preeclampsia is 3-5% in nulliparae and 0.5% in multiparae. Preeclampsia is a severe and dangerous pathology with an unknown etiology. Pregnancy termination is the only causal therapy. At present it is still recommended to terminate a severe preeclampsia after stabilizing the mother, irrespective of gestational age. In less severe preeclampsia occurring before 32 weeks of gestation, termination of pregnancy can be postponed under intensive monitoring and a prophylaxis with magnesium sulfate in order to accelerate the fetal lung maturation with glucocorticoids. A conservative management in the case of a HELLP-syndrome (Haemolyis, Elevated Liver enzymes, Low Platelets), which is a very severe form of preeclampsia, is not recommended because it hasn't been validated in prospective controlled studies. The most dangerous complication of preeclampsia is eclampsia, which is defined by general tonic-clonic convulsions before or after birth. The most effective prophylaxis of eclamptic attacks is the intravenous therapy with magnesium sulfate. A primary prohylaxis for preeclampsia doesn't exist. Treatment with low-dose aspirin in high-risk patients, i.e. after a severe preeclampsia, in cases of chronic hypertension, in cases of nephropathy and in cases with antiphospholipid-syndrome++ can be recommended. The prophylactic use of low-dose heparin, which has lead to a significant decreased incidence of preeclampsia in retrospective analysis, is now the object of a randomized, controlled trial in our hospital. All women who suffered from a preeclampsia should have a check-up after 3-6 months. Preexisting pathologies are found in up to 40% of patients, mostly in multiparae, i.e. chronic hypertension, nephropathy, endocrine pathologies, anomalies of blood coagulation and antiphospolipid-syndrome.