Chronic hypertension in pregnancy

Definition

• Chronic hypertension is present when blood pressure is already raised before pregnancy or is at least 140 mmHg systolic or at least 90 mmHg diastolic on two occasions before 20 weeks of gestation.

Classification

• It belongs to the hypertensive disorders of pregnancy and occurs with or without superimposed pre-eclampsia or eclampsia.
• Values of 160 mmHg systolic and/or 110 mmHg diastolic or higher are considered severe.

Occurrence & epidemiology

Epidemiology

• Chronic hypertension complicates about 1–5% of all pregnancies; gestational hypertension occurs in about 5–10%.

Aetiopathogenesis

Aetiology and risk factors

• Besides primary hypertension, secondary causes such as renal artery stenosis, coarctation of the aorta, Cushing syndrome, systemic lupus erythematosus or phaeochromocytoma may be involved.
• Chronic hypertension is regarded as a high-risk factor for pre-eclampsia.

Clinical features

Clinical features and complications

• For the mother, the risk of pre-eclampsia and eclampsia, hypertensive encephalopathy, stroke, renal failure, left ventricular failure and HELLP syndrome increases.
• Reduced uteroplacental blood flow can cause fetal growth restriction, hypoxia and placental abruption; outcomes are worse with severe hypertension or renal insufficiency.

Diagnosis

• Blood pressure is measured at every antenatal visit; when severe hypertension appears for the first time without multiple pregnancy or trophoblastic disease, secondary causes are investigated.

Keep learning in the app

Further reading (selection)

1. StatPearls: Hypertension In Pregnancy (NCBI Bookshelf)
2. MSD Manual Professional Edition: Hypertension in Pregnancy
3. MSD Manual Professional Edition: Preeclampsia and Eclampsia

Cross-references