Management of Hypertension in Pregnancy - Current Guidelines

Classification of Hypertensive Disorders of Pregnancy - Comprehensive Clinical Nephrology, 7th Ed.

1. Classification

2. Preeclampsia Diagnosis (Updated Criteria)

• Proteinuria (uPCR >30 mg/mmol or ≥300 mg/24 h)
• AKI (creatinine ≥1 mg/dL above baseline, or ≥2x baseline)
• Thrombocytopenia (platelets ≤100,000/µL)
• Liver dysfunction (transaminases ≥2x ULN)
• Pulmonary edema
• Neurological features (severe headache, visual scotomata, seizures)
• Uteroplacental dysfunction (fetal growth restriction, abnormal umbilical artery Doppler)

3. BP Treatment Thresholds - Where Guidelines Diverge

4. Antihypertensive Drug Selection

4A. Drugs Safe in Pregnancy (Oral - Chronic/Non-urgent)

4B. IV Drugs for Acute/Severe Hypertension (SBP ≥160 or DBP ≥110)

4C. Contraindicated Drugs

• ACE inhibitors - fetal renal dysplasia, oligohydramnios, pulmonary hypoplasia (especially 2nd/3rd trimester)
• Angiotensin receptor blockers (ARBs) - same as ACE inhibitors
• Atenolol - associated with fetal growth restriction
• Direct renin inhibitors - not recommended
• Spironolactone - theoretical risk of inadequate virilization of male fetuses

5. Preeclampsia - Specific Management

5A. Severity Assessment

5B. Magnesium Sulfate (Seizure Prophylaxis)

• Indicated in preeclampsia with severe features, particularly CNS involvement (clonus, severe headache, visual scotomata)
• Loading dose: 4-6 g IV over 15-20 min; maintenance 1-2 g/h infusion
• Monitor: respiratory rate, O2 saturation, reflexes, ECG
• Avoid routine serum Mg levels unless renal impairment present (dose reductions needed in CKD)
• Withholding Mg2SO4 in preeclampsia without severe features is associated with extremely low seizure risk and avoids drug toxicity (up to 25% experience toxicity)
• ~20% of eclampsia occurs >48 h postpartum - continue treatment

5C. Fluid Management

• Preeclampsia is a volume-contracted, not volume-depleted state with increased capillary permeability
• IV fluid restriction (~85 mL/h) in severe features reduces maternal morbidity and mortality
• Volume expansion is NOT warranted - high risk of pulmonary edema
• Invasive monitoring of central pressure is not indicated

5D. Platelet Transfusion (HELLP)

• Indicated for platelets <20-30 × 10⁹/L to facilitate delivery
• Avoid at higher counts - pathology is consumptive, not deficiency
• No evidence for plasma exchange or corticosteroids in HELLP syndrome

6. Delivery Timing

• Progressive end-organ dysfunction (kidney, liver, CNS, thrombocytopenia)
• Inability to control BP
• Failure of fetal growth or compromised fetal status

7. Prevention of Preeclampsia

Low-Dose Aspirin

• Recommended for all women at high risk (prior preeclampsia, chronic hypertension, diabetes types 1/2, renal disease, autoimmune conditions, multiple gestation)
• Dose: 75-150 mg/day (most guidelines use 100-150 mg)
• Start ideally before 16 weeks gestation; evidence shows 43% risk reduction when started early
• Cochrane review of 59 trials: 17% reduction in preeclampsia risk overall
• RCT (Rolnik et al.): 150 mg aspirin from 11-14 weeks in high-risk women - OR 0.38 (95% CI 0.20-0.74) for preeclampsia

Calcium Supplementation

• WHO recommends 1.5-2 g/day after 20 weeks in women with low calcium intake
• Cochrane review: ~50% reduction in preeclampsia with high-dose calcium supplementation (>1 g/day), greatest benefit in low-calcium diet and high-risk women
• Not given routinely in most high-income countries

Not Recommended

• Vitamins C and E (associated with worse outcomes)
• Fish oils, folic acid, magnesium, garlic supplements
• Anticoagulation for preeclampsia prevention alone

8. Postpartum Management

• BP typically improves after delivery but can worsen in the first 3-5 days postpartum
• Women with preeclampsia are at continued risk for eclampsia for at least 48-72 h postpartum
• Methyldopa should be avoided postpartum (risk of depression)
• NSAIDs should be avoided if hypertension is difficult to control postpartum
• Breastfeeding-compatible antihypertensives: nifedipine, labetalol, methyldopa
• ACE inhibitors (enalapril, captopril) are acceptable postpartum for non-breastfeeding women
• Recent RCT (Marques et al., PMID 39884047, 2025): evaluated early postpartum hypertension management

Long-Term Follow-Up

• Preeclampsia significantly increases lifetime cardiovascular risk: chronic HTN risk (RR 3.6-3.7), CVD risk, CKD
• Cardiovascular risk assessment recommended at 3 months postpartum and annually thereafter

9. Special Situations

Chronic Hypertension Pre-pregnancy Counseling

• Screen for secondary causes: renal artery stenosis, pheochromocytoma, primary hyperaldosteronism, OSA (40% of women with HTN in pregnancy have OSA by polysomnography)
• Switch to pregnancy-safe antihypertensives pre-conception
• Counsel on risks: preeclampsia, preterm birth, IUGR

Secondary Hypertension in Pregnancy

• Fibromuscular dysplasia/renovascular HTN: consider MR angiography; angioplasty has been done in 2nd/3rd trimester
• Pheochromocytoma: devastating if missed - suspect with paroxysmal severe hypertension
• Primary hyperaldosteronism: spironolactone has theoretical fetal risk; eplerenone is safer alternative
• OSA: screen high-risk women (snoring, obesity); treat with CPAP

• Brenner and Rector's The Kidney (Comprehensive Clinical Nephrology)
• Comprehensive Clinical Nephrology, 7th Edition
• NKF Primer on Kidney Diseases, 8th Ed.
• Goodman & Gilman's The Pharmacological Basis of Therapeutics
• Fuster and Hurst's The Heart, 15th Ed.
• ACOG Practice Bulletin #203 / 2024 ACOG Annual Meeting update (CHAP trial-based)
• ISSHP 2021 Classification and Management Recommendations
• CHIPS Trial (Control of Hypertension in Pregnancy Study)
• PubMed: PMID 38949541 (nifedipine vs labetalol RCT 2024), PMID 39884047 (postpartum HTN management RCT 2025)