Table 3: Proposed classification of hypertensive disorders in pregnancy
Classification	Definition
A. Pre-existing hypertension	Diastolic hypertension (as defined in Table 1) that predates pregnancy or is diagnosed before 20 weeks' gestation. In most cases hypertension persists > 42 d post partum. It may be associated with proteinuria.
1. Essential	Primary
2. Secondary	Secondary to such conditions as renal disease, pheochromocytoma and Cushing syndrome
B. Gestational hypertension	Diastolic hypertension develops after 20 weeks' gestation. In most cases it resolves < 42 d postpartum
1. Without proteinuria	Corresponds to previous terminology such as "pregnancy-induced hypertension," "transient hypertension" and "nonproteinuric hypertension." Protein excretion in 24­hour urine collection is < 0.3 g/d
a. Without adverse conditions
b. With adverse conditions	Convulsions (eclampsia); very high diastolic pressure (> 110 mm Hg); thrombocytopenia (platelet count < 100 000 X 109/L); oliguria (< 500 mL/d); pulmonary edema; elevated liver enzyme levels; severe nausea and vomiting, frontal headache, visual disturbances, persistent abdominal pain in right upper quadrant, chest pain or shortness of breath; suspected abruptio placentae; HELLP syndrome; intrauterine growth retardation, oligohydramnios, or absent or reversed umbilical artery end diastolic flow, as determined by Doppler velicitometry
2. With proteinuria	Corresponds to previous terminology such as "pre­eclampsia," "pre-eclamptic toxemia" and "toxemia." Protein excretion in 24-hour urine collection is 0.3 g/d
a. Without adverse conditions
b. With adverse conditions	Same conditions as in 1b; protein excretion > 3 g/d in 24-h urine collection, especially with hypoalbuminemia (albumin level < 18 g/L)
C. Pre-existing hypertension + superimposed gestational hypertension with proteinuria	Pre-existing hypertension (as defined in A) associated with further worsening of blood pressure and protein excretion  3 g/d in 24-h urine collection after 20 weeks' gestation. Corresponds to previous terminology "chronic hypertension with superimposed pre-eclampsia"
D. Unclassifiable antenatally	Hypertension with or without systemic manifestations if blood pressure was first recorded after 20 weeks' gestation. Reassessment is necessary at or after 42 d post partum. If the hypertension has resolved by then, the condition should be reclassified as gestational hypertension with or without proteinuria; if the hypertension has not resolved by then, the condition should be reclassified as pre-existing hypertension

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