Table 1.

Types of hypertension that can occur in pregnancy²

Hypertension	Definition	Prevalence	Risk factors
Chronic hypertension	SBP≥140 or DBP≥90 mm Hg before pregnancy or before 20 weeks of gestation	14% of pregnancies	Obesity, a family history of hypertension, advanced maternal age.
Gestational hypertension	SBP≥140 or DBP≥90 mm Hg after 20 weeks of gestation	2%–5% of pregnancies	(Pre)gestational diabetes, pre-eclampsia in a previous pregnancy, nulliparity, twin pregnancy, obesity, pregnancy via assisted reproductive technology and born of an HDP pregnancy
Pre-eclampsia	SBP≥140 or DBP≥90 mm Hg after 20 weeks of gestation and the presence of proteinuria (≥300 mg/day or ≥1 g/L on dipstick testing), maternal organ dysfunction (renal insufficiency, liver involvement, neurological complications (including eclampsia) or thrombocytopenia) or fetal growth restriction	2%–5% of pregnancies	Those mentioned under gestational hypertension and antiphospholipid antibody syndrome, maternal age<18 or >35 years, black race, first degree relative with pre-eclampsia, migraine, SSRI use after the first trimester, thrombophilia, chronic kidney disease and autoimmune disease
Superimposed pre-eclampsia	SBP≥140 or DBP≥90 mmHg before pregnancy or before 20 weeks of gestation with a new-onset proteinuria or an acute exacerbation of hypertension or proteinuria in the second half of pregnancy or sudden systemic features of pre-eclampsia		Previous pre-eclampsia

DBP, diastolic blood pressure; HDP, hypertensive disorder of pregnancy; SBP, systolic blood pressure; SSRI, selective serotonin reuptake inhibitor.