Hypertension in Pregnancy

Definition

Hypertension in pregnancy refers to elevated blood pressure (≥140/90 mmHg) occurring during pregnancy, which can be classified as chronic hypertension, gestational hypertension, preeclampsia, or eclampsia.

Epidemiology

• Affects approximately 5–10% of pregnancies worldwide.
• Leading cause of maternal and perinatal morbidity and mortality.
• Risk increases with advanced maternal age, obesity, pre-existing hypertension, diabetes, or renal disease.
• More common in first pregnancies and multiple gestations.
• Higher incidence in low- and middle-income countries due to limited prenatal care.

Etiology

• Chronic hypertension: pre-existing before pregnancy or diagnosed before 20 weeks gestation.
• Gestational hypertension: new-onset hypertension after 20 weeks without proteinuria.
• Preeclampsia: hypertension with proteinuria or signs of end-organ dysfunction after 20 weeks.
• Eclampsia: preeclampsia complicated by seizures.
• Risk factors: family history, multiple gestation, obesity, advanced maternal age, renal disease, autoimmune disorders.

Pathophysiology

• Abnormal placentation leading to endothelial dysfunction and vasoconstriction.
• Increased systemic vascular resistance and blood pressure.
• Imbalance between pro-angiogenic and anti-angiogenic factors (e.g., sFlt-1, PlGF) in preeclampsia.
• Reduced renal perfusion and glomerular injury contributing to proteinuria.
• Activation of coagulation cascade, oxidative stress, and inflammatory pathways.