Proposed classification by Brown and Buddle

1. Pre-eclampsia

De novo hypertension arising after 20 weeks gestation returning to normal within 3 months postpartum and one or more of the following:

• Proteinuria>=300mg.day, spot urine protein:creatinine >=30mg/mol or dipstick persistently >= 1g/l
• Renal insufficiency, plasma creatinine >=0.1mmol/l
• Liver disease, AST.40IU/l and/or severe epigastric-right upper quadrant pain
• Neurological problems, convulsions (eclampsia); hyperreflexia with clonus; severe headaches with hyperreflexia
• Haematological disturbances, thrombocytopenia; haemolysis
• Fetal growth retardation

2. Gestational hypertension

De novo hypertension after 20 weeks gestation without any other feature of pre-eclampsia, returning to normal within 3 months postpartum

3. Chronic hypertension

(a) Essential hypertension: BP >=140 mmHg systolic and/or 90 mmHg diastolic pre-conception or in the first half of pregnancy without an apparent secondary cause or evidence of 'white-coat hypertension
(b) Secondary hypertension

4. Superimposed hypertension, the new development after 20 weeks gestation of one or more of the features of pre-eclampsia listed above

NOTES:
HT in pregnancy is defined as an absolute BP>=140mmHg systolic and/or 90 mmHg diastolic, or else a rise in systolic BP>=25 mmHg. Oedema is not included in any part of this classification system. Proteinuria is mandatory for a clinical diagnosis of pre-eclampsia.