Management of Hypertension in Pregnancy

Classification

BP Measurement in Pregnancy

• Office BP remains standard; confirm with repeat readings ≥4 hours apart.
• HBPM and ABPM should be considered to exclude white-coat and masked hypertension, which are more common in pregnancy (ESC 2024, Class IIa).
• Use validated devices; patient should be seated, arm at heart level.

Prevention of Preeclampsia

• Low-dose aspirin (75–150 mg/day) starting at 11–16 weeks is recommended in women at high risk of preeclampsia (ESC 2024 Class I; ISSHP 2021).
• Calcium supplementation (1.5–2 g/day) in women with low dietary calcium intake reduces preeclampsia risk.
• Low-to-moderate intensity exercise is recommended in all pregnant women without contraindications to reduce risk of gestational HTN and preeclampsia (ESC 2024, Class I).
• Weight loss and dietary sodium restriction have not been validated in pregnancy; these non-pharmacological strategies are not routinely recommended.

Treatment Thresholds and BP Targets

ESC 2024 (most current guidelines)

• In chronic or gestational hypertension: start drug treatment at confirmed office BP ≥140/90 mmHg (Class I, Level B).
• Target: <140/90 mmHg, but diastolic BP not below 80 mmHg to avoid placental hypoperfusion.
• BP ≥170/110 mmHg = obstetric emergency; admit to hospital (Class I).
• BP ≥160/110 mmHg = possible emergency; immediate hospitalization should be considered (Class IIa).

CHIPS Trial Evidence

• No significant difference in pregnancy loss or high-level neonatal care.
• Women in the tight-control arm had significantly fewer episodes of severe HTN, thrombocytopenia, and elevated transaminases.
• Conclusion: Treating to DBP ~85 mmHg is safe for the fetus and reduces maternal complications.

Pharmacological Management

Oral Agents for Chronic/Gestational Hypertension

Acute/Severe Hypertension (BP ≥160/110 mmHg)

• IV labetalol — 20 mg IV bolus; escalate to 40 mg at 10 min if needed
• IV hydralazine — 5–10 mg IV/IM, repeat at 20-min intervals
• Oral nifedipine (immediate-release) — 10–20 mg, can repeat in 30 min
• IV nicardipine — alternative, especially in preeclampsia

Contraindicated Drugs

• ACE inhibitors and ARBs — fetal renal dysplasia, oligohydramnios, pulmonary hypoplasia (2nd/3rd trimester exposure is teratogenic; avoid throughout pregnancy)
• Direct renin inhibitors (aliskiren) — contraindicated
• Spironolactone — theoretical risk of inadequate virilization of male fetuses

Preeclampsia: Specific Management

Antepartum

• Delivery is the definitive treatment.
• At ≥37 weeks with preeclampsia: deliver.
• At <34 weeks with severe features: consider hospitalization, IV antihypertensives, and magnesium sulfate for seizure prophylaxis, with steroid administration for fetal lung maturation if <34 weeks; plan early delivery.
• At 34–37 weeks: individualized based on severity.

Magnesium Sulfate

• Indicated in severe preeclampsia and eclampsia for seizure prophylaxis (not treatment of hypertension).
• Also indicated in women with CNS manifestations (headache, visual disturbances, altered consciousness).
• Continue for ≥24 hours postpartum — ~20% of eclamptic episodes occur >48h after delivery.

HELLP Syndrome

• Defined by: Hemolysis + Elevated Liver enzymes + Low Platelets
• Management parallels severe preeclampsia — magnesium sulfate, antihypertensives, delivery planning.

Fetal Monitoring

Secondary Hypertension in Pregnancy

• Renal artery stenosis (fibromuscular dysplasia) — suspect if severe, resistant HTN; MR angiography preferred
• Pheochromocytoma — fatal if missed; screen with urinary metanephrines
• Primary hyperaldosteronism — hypertension + hypokalemia; plasma aldosterone/renin ratio not validated in pregnancy
• Obstructive sleep apnea — 40% of women with HTN in pregnancy in one study; screen high-risk patients (obese, snoring)

Postpartum Management

• BP often rises postpartum (days 3–5) — close monitoring is essential.
• Continue antihypertensives; many agents are safe during breastfeeding (labetalol, nifedipine, methyldopa).
• ACE inhibitors (enalapril, captopril) can be used postpartum/breastfeeding when clinically needed.
• NSAIDs — avoid in hypertensive postpartum women (can worsen BP).
• HBPM-guided self-monitoring recommended for titration (ESC 2024, Class I).
• Discharge BP target: <150/100 mmHg; ideally <140/90 mmHg before stopping formal monitoring.

Long-term Risk After Hypertensive Pregnancy

• 2–4× increased risk of stroke (meta-analysis, PMID 36990309)
• Increased future risk of chronic hypertension, ischemic heart disease, and dementia
• Annual BP check and cardiovascular risk assessment recommended for life.

Key Guideline Sources

• 2024 ESC Guidelines for Management of Elevated Blood Pressure (Section 9.2 — Hypertension in Pregnancy)
• ISSHP 2021 — Classification, Diagnosis & Management of Hypertensive Disorders of Pregnancy
• ACOG — Hypertension in Pregnancy Task Force (threshold update 2022: treatment at ≥140/90 mmHg)
• FOGSI-GESTOSIS-ICOG Good Clinical Practice Recommendations 2026
• Brenner & Rector's The Kidney; NKF Primer on Kidney Diseases 8e; Goodman & Gilman's Pharmacological Basis of Therapeutics