Hypertension in pregnancy

Overview

Hypertension in pregnancy is one of the main causes of maternal, fetal and newborn morbidity and mortality in civilised countries. Current recommendations of the European Society for Hypertension prefer definition of hypertension in pregnancy based on absolute values of blood pressure, i.e. systolic blood pressure ≥ 140 mm Hg or diastolic blood pressure ≥ 90 mm Hg. The most important task of classification of hypertension in pregnancy is to distinguish whether hypertension comes before pregnancy (the so called pre-existing hypertension) or whether it is a pregnancy-induced condition (the so called gestational hypertension). Pre-existing hypertension is diagnosed either before pregnancy or within the first 20 weeks of pregnancy. Gestational hypertension is characterised with poor blood circulation in many body organs, higher value of blood pressure usually being just one of the characteristic features. Non-pharmacological treatment of hypertension must be considered in pregnant women with systolic blood pressure 140–150 mm Hg or diastolic blood pressure 90–99 mm Hg. Salt restriction is not recommended, as well as weight reduction in obese women. Systolic blood pressure ≥ 170 mm Hg or diastolic blood pressure ≥ 110 mm Hg in pregnant women must be considered serious condition necessitating hospitalisation. Pharmacological therapy should include labetalol i.v. or metyldopa or nifedipin administered orally. Intravenous administration of dihydralazine is no longer a therapy of choice, for its use is connected with increased occurrence of adverse effects. The threshold values for commencement of anti-hypertension therapy are systolic blood pressure 140 mm Hg or diastolic blood pressure 90 mm Hg in females with gestational hypertension without proteinuria or with pre-existing hypertension before commencement of 28th week of pregnancy. Drug administration to reduce hypertension is instituted after reaching the same threshold values in females with gestational hypertension and proteinuria or after occurrence of the symptoms any time during pregnancy, with the same threshold values of blood pressure in the case of pre-existing hypertension at the presence of accompanying diseases or organ malfunction and further in the case of pre-existing hypertension and gestational hypertension. In other cases drug treatment of hypertension is recommended at systolic blood pressure values of 150 mm Hg or diastolic blood pressure values of 95 mm Hg. Unless serious hypertension is involved, the drugs of choice include metyldope, labetalol, calcium channel blockers and betablockers. Calcium channel blockers are considered safe, unless administered concurrently with magnesium sulphate (risk of hypotension in the case of potential synergism). ACE inhibitors and angiotensine blockers II (AT1-blockers) are contraindicated in pregnancy. Treatment with diuretics is not substantiated, unless oliguria is present. I.v. magnesium sulphate is recommended for prevention of eclampsia and spasm treatment.

Key words:
pre-existing hypertension – gestational hypertension – non-pharmacological treatment of hypertension – metyldopa – labetalol – calcium channel blockers – magnesium sulphate