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Hypertensive disorders seriously complicate approximately 2% to 8% of all pregnancies.1 Indeed, 19% of pregnancy-related maternal mortality is due to complications related to hypertensive disorders.2 Hypertensive disorders during pregnancy involve a variety of clinical entities, including gestational hypertension, preeclampsia, eclampsia, chronic hypertension, superimposed preeclampsia on chronic hypertension, and hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome.3 The normal physiologic changes of pregnancy result in a net reduction of systolic, diastolic, and mean arterial blood pressure by midpregnancy because of decreased systemic vascular resistance and the presence of a low resistance to flow placenta. At the end of term pregnancy, the blood pressure returns to baseline prepregnant level.4
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Gestational hypertension occurs when a pregnant woman without a previous history develops isolated hypertension (greater than 140/90 mm Hg) after 20 weeks’ gestation. It is not associated with significant proteinuria or other symptoms and signs of preeclampsia and resolves within 12 weeks’ postpartum.
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Preeclampsia is diagnosed when a pregnant woman develops new onset hypertension (greater than 140/90 mm Hg) after 20 weeks’ gestation often in conjunction with proteinuria (greater than 300 mg in a 24-hour collection). In 2013, the American College of Obstetricians and Gynecologists (ACOG) updated its diagnostic criteria of preeclampsia-eclampsia and eliminated the dependence on proteinuria for diagnosis. To reflect the syndromic nature of preeclampsia, in the absence of proteinuria, it is diagnosed as hypertension in association with thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema, or cerebral or visual disturbances.5 Preeclampsia may be classified as severe based on any of the following:
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Systolic blood pressure greater than or equal to 160 mm Hg, or diastolic blood pressure greater than or equal to 110 mm Hg
Thrombocytopenia (platelet count less than or equal to 100,000/mm3)
Impaired liver function as indicated by elevated liver enzymes (to twice normal levels) and/or severe persistent right upper quadrant pain
Renal insufficiency as indicated by serum creatinine concentration greater than 1.1 mg/dL or a doubling of the serum creatinine
Pulmonary edema
New-onset cerebral or visual disturbances
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The most recent report of ACOG’s task force on hypertension in pregnancy has eliminated proteinuria greater than 5 g from the diagnostic criteria for severe preeclampsia for the reason that there is a minimal relationship between the quantity of urinary protein and pregnancy outcome.5
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Eclampsia is defined by new-onset seizures or impaired mental state (ie, coma) in a preeclamptic woman. It is not a separate entity from preeclampsia but rather signifies a continuum of severity. Eclampsia carries a high maternal morbidity and mortality rate. Intracerebral hemorrhage/stroke, pulmonary aspiration, cardiopulmonary arrest, acute renal failure, and death are major complications of seizures. In addition, there is significant potential for fetal jeopardy.6
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HELLP syndrome is considered a variant of preeclampsia. Aside from hemolysis, elevated liver enzymes, and low platelets, associated symptoms may include hypertension, ...