Superimposed preeclampsia may develop in a patient with existing chronic hypertension. The diagnosis is made if:

• In women with chronic hypertension and NO proteinuria prior to 20 weeks gestation: there is new-onset proteinuria (0.5 gm in 24 hour collection).

• In women with chronic hypertension AND proteinuria prior to 20 weeks gestation: there is significant worsening of hypertension AND
  • Development of symptoms such as headache or right upper quadrant pain, AND/OR
  • Abnormal liver enzymes or thrombocytopenia

• The presence or absence of peripheral edema is not considered in the diagnosis of preeclampsia.