Table I.

 Defining HTN Disorders of Pregnancy

HTN Disorder	Onset	Proteinuria (>300 mg/d)? Yes/No	Prevalence
Chronic HTN	Prior to pregnancy, recognized <20 wk gestation	No	3% of all pregnancies
Gestational HTN	≥20 wk gestation; usually presents in 3rd trimester	No	6%–17%, nulliparous 2%–4%, multiparous  women
Preeclampsia	>20 wk gestation; usually presents in 3rd trimester	Yes (Onset of HTN and proteinuria are not necessarily concurrent)	5%–8% of all pregnancies; 20% among diabetic women
Preeclampsia superimposed on chronic HTN	Chronic HTN: ≤20 wk gestation PE: >20 wk gestation	Yes	25% of women with chronic HTN develop superimposed preeclampsia

Abbreviations: HTN, hypertension; PE, preeclampsia.