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Table 1 Classification of preeclampsia among cases (N = 113)

From: Smoking in preeclamptic women is associated with higher birthweight for gestational age and lower soluble fms-like tyrosine kinase-1 levels: a nested case control study

  Total Early-onsetb Severec
Canadian Hypertension Society classification a    
Gestational hypertension with proteinuria without adverse conditions 12 (11%) 3 (8%) 0 (0%)
Gestational hypertension with proteinuria with adverse conditions 49 (43%) 16 (46%) 19 (59%)
Gestational hypertension without proteinuria with adverse conditions 49 (43%) 14 (40%) 10 (31%)
Chronic hypertension with superimposed preeclampsia 3 (3%) 2 (6%) 3 (10%)
TOTAL 113 (100%) 35 (100%) 32 (100%)
  1. a Diagnostic criteria used for preeclampsia and non-preeclamptic hypertensive disorders of pregnancy were adapted from the 1997 Report of the Canadian Hypertension Society Consensus Conference [12]. Gestational hypertension was defined as diastolic hypertension (≥ 90 mm Hg) on two occasions at least 4-6 hours apart that developed after 20 wks gestation. Proteinuria was defined as protein excretion of ≥ 0.3 g/day in 24-hour urine collection or positive dipstick result ≥ 2+. Adverse conditions were defined as convulsions (eclampsia), diastolic pressure > 110 mm Hg, platelet count < 100,000 × 109/L, oliguria, protein excretion ≥ 3 g/day, pulmonary edema, elevated liver enzymes, 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 restriction, oligohydramnios, or absent or reverse umbilical artery end diastolic flow, as detected by Doppler velocitometry. Chronic hypertension with superimposed preeclampsia was defined as known chronic hypertension associated with further worsening of blood pressure and protein excretion ≥ 3 g/day after 20 weeks gestation. Non-preeclamptic hypertensive disorders (criterion for exclusion as case or control) included gestational hypertension, defined as diastolic hypertension (≥ 90 mm Hg) that developed after 20 wks gestation but without proteinuria or adverse conditions, and chronic known hypertension, defined as diastolic hypertension (≥ 90 mm Hg) that predated pregnancy or was diagnosed before 20 wks gestation, with or without proteinuria.
  2. b Early-onset preeclampsia defined as occurrence at < 34 weeks gestation [18]
  3. c Severe preeclampsia defined as presence of any of the following: seizure, HELLP, proteinuria ≥ 3 g/24 hours or diastolic blood pressure > 110 mm Hg [18]