How to manage hypertension in a pregnant patient?

Management of Hypertension in Pregnancy

For pregnant women with hypertension, initiate treatment with extended-release nifedipine, labetalol, or methyldopa when blood pressure reaches ≥140/90 mmHg, targeting a blood pressure of 110-140/85 mmHg, and urgently treat any blood pressure ≥160/110 mmHg within 60 minutes to prevent maternal stroke. 1, 2

Immediate Medication Discontinuation

• Stop ACE inhibitors, ARBs, direct renin inhibitors, mineralocorticoid receptor antagonists, and neprilysin inhibitors immediately upon pregnancy confirmation or when planning conception, as these cause severe fetal teratogenicity, oligohydramnios, and renal dysgenesis 1, 2, 3
• Transition to pregnancy-safe alternatives (nifedipine, labetalol, or methyldopa) before attempting conception in women of childbearing potential 2, 4

Blood Pressure Treatment Thresholds and Targets

Chronic Hypertension

• Initiate antihypertensive therapy at ≥140/90 mmHg for all pregnant women with confirmed hypertension 1, 2
• Target blood pressure: 110-140 mmHg systolic and 85 mmHg diastolic 1, 2
• Never allow diastolic BP to fall below 80 mmHg to maintain adequate uteroplacental perfusion 1, 2

Severe Hypertension (Hypertensive Emergency)

• Treat urgently when BP ≥160/110 mmHg lasting >15 minutes to prevent maternal cerebrovascular complications including stroke 1, 2, 5
• Treatment must be initiated within 60 minutes of the first severe reading 1

First-Line Pharmacological Management

Preferred Medications (in order of preference)

1. Extended-Release Nifedipine (First Choice)

• Dosing: Start 30-60 mg once daily, titrate up to maximum 120 mg daily 1, 6, 2
• Advantages: Once-daily dosing improves adherence; strongest safety data in pregnancy 6, 2
• Critical safety warning: Use only long-acting formulations for maintenance therapy; never use sublingual or immediate-release for chronic management due to risk of precipitous hypotension and maternal myocardial infarction 6, 3
• Contraindication: Do not administer concurrently with IV magnesium sulfate due to risk of severe hypotension and myocardial depression 6, 3

2. Labetalol (Equally Effective Alternative)

• Dosing: Start 100 mg twice daily, titrate up to maximum 2400 mg/day in divided doses 6, 7
• Advantages: Comparable efficacy and safety to nifedipine 6, 2
• Disadvantages: Requires TID or QID dosing due to accelerated metabolism in pregnancy, which may reduce adherence 6
• Contraindications: Reactive airway disease (asthma/COPD); avoid atenolol specifically due to higher risk of fetal growth restriction 6, 7
• Potential adverse effects: Neonatal bradycardia, hypoglycemia, and possible small-for-gestational-age infants 6, 7

3. Methyldopa (Third-Line Option)

• Dosing: Titrate as needed for blood pressure control 1, 8
• Advantages: Longest safety record with documented follow-up of children to 7.5 years of age; may reduce mid-trimester abortion risk 6, 5
• Disadvantages: Associated with postpartum depression; should be switched to alternative agent (nifedipine or labetalol) after delivery 9, 6, 8
• Important caveat: Less effective than labetalol or nifedipine in preventing preeclampsia 6

Acute Severe Hypertension Management (≥160/110 mmHg)

Immediate-Release Oral Nifedipine Protocol

• Give 10-20 mg immediate-release nifedipine orally (never sublingual) 1, 6
• Repeat every 20-30 minutes if BP remains ≥160/110 mmHg 1, 6
• Maximum total dose: 30 mg in the first hour 6
• Monitor blood pressure closely in the first hour after administration 6

IV Labetalol Protocol (if oral route unavailable)

• Initial dose: 20 mg IV bolus 6
• Repeat with escalating doses (40 mg, 80 mg) every 10 minutes 6
• Maximum cumulative dose: 300 mg 6, 7

IV Hydralazine (Alternative)

• Acceptable for acute severe hypertension when other agents are unavailable 1, 5

Medications to Avoid During Pregnancy

Absolutely Contraindicated

• ACE inhibitors, ARBs, direct renin inhibitors, mineralocorticoid receptor antagonists (cause fetal renal dysgenesis and teratogenicity) 1, 2, 3
• Atenolol (higher risk of fetal growth restriction compared to other beta-blockers) 6

Not Recommended

• Diuretics: Reduce uteroplacental perfusion and plasma volume expansion; not used for blood pressure management in pregnancy 1, 2
• Exception: May be continued if already taking for volume control in late pregnancy, but not initiated for hypertension 1

Monitoring Requirements

Gestational Hypertension Monitoring

• Urinalysis at each visit to monitor for developing preeclampsia 1
• Blood tests at minimum at 28 and 34 weeks: Complete blood count (hemoglobin, platelets), liver transaminases, uric acid, creatinine 1
• Fetal ultrasound from 26 weeks' gestation, then every 2-4 weeks if normal biometry; more frequently if growth restriction suspected 1

Severe Hypertension/Preeclampsia Monitoring

• Blood pressure monitoring at least every 4 hours while awake for first 3 days postpartum 9
• Consider ICU transfer if: need for respiratory support, tachypnea, severe electrolyte abnormalities, need for pressor support, abnormal ECG requiring intervention, or failure of first-line IV antihypertensives 9

Timing of Delivery

Gestational Hypertension Without Preeclampsia

• Delivery can be delayed until 39+6 weeks provided BP is controlled, fetal monitoring is reassuring, and preeclampsia has not developed 1
• If no complications arise, delivery at 39 weeks appears optimal 1

Preeclampsia or Severe Hypertension

• Delivery timing depends on severity of maternal condition and gestational age 1
• Consider deferring delivery only if fetus is significantly premature (<34 weeks), no maternal or fetal distress, and meticulous monitoring is possible 5

Postpartum Management

Blood Pressure Monitoring

• Close monitoring for at least 3 days postpartum with BP checks at least 4-6 times daily 9, 2
• Blood pressure often worsens between days 3-6 postpartum 9, 6
• Treat any hypertension before day 6 postpartum with antihypertensive therapy 9

Medication Adjustments

• Continue antihypertensive medications postpartum with gradual tapering rather than abrupt cessation 9, 2
• Switch from methyldopa to nifedipine or labetalol postpartum due to methyldopa's association with postpartum depression 9, 6
• Consider transitioning to once-daily agents (extended-release nifedipine, amlodipine, or enalapril) for better adherence 6

Safe Medications for Breastfeeding

• Labetalol, nifedipine, methyldopa, enalapril, and metoprolol are safe for breastfeeding mothers 9, 6, 2
• Avoid diuretics as they may reduce milk production and suppress lactation 9, 6
• Avoid NSAIDs in women with preeclampsia as they worsen hypertension and impair renal function 9, 6

Follow-Up Timeline

• Review within 1 week if still requiring antihypertensives at hospital discharge 6
• Comprehensive review at 3 months postpartum to ensure BP, urinalysis, and laboratory abnormalities have normalized 9, 2
• If hypertension persists beyond 12 weeks postpartum, this suggests pre-existing chronic hypertension rather than gestational hypertension 9
• Women under age 40 with persistent hypertension should be assessed for secondary causes 9

Long-Term Cardiovascular Risk Management

• Women with hypertensive disorders of pregnancy have significantly elevated lifetime risk of cardiovascular disease, stroke, ischemic heart disease, and thromboembolic disease 9, 2, 10
• Annual medical review is advised lifelong for cardiovascular risk assessment 9, 2
• Aim to achieve pre-pregnancy weight by 12 months and limit interpregnancy weight gain 9
• Adopt healthy lifestyle including regular exercise, healthy diet, and maintaining ideal body weight 9, 2
• Regular monitoring of BP and periodic measurement of fasting lipids and blood glucose 9

Non-Pharmacological Management

• Low to moderate-intensity exercise for all pregnant women without contraindications reduces risk of gestational hypertension and preeclampsia 2
• Normal diet without salt restriction is advised, particularly close to delivery, as salt restriction may induce low intravascular volume 2
• Calcium supplementation (≥1 g daily) reduces risk of preeclampsia, particularly in high-risk women 6
• Avoid grapefruit juice as it increases nifedipine levels by 2-fold; stop at least 3 days prior to initiating nifedipine 3

Critical Pitfalls to Avoid

• Never use immediate-release nifedipine for maintenance therapy due to risk of uncontrolled hypotension, especially when combined with magnesium sulfate 6, 3
• Do not allow diastolic BP to fall below 80 mmHg as this compromises uteroplacental perfusion 1, 2
• Controlling blood pressure does not mask preeclampsia as other diagnostic features (proteinuria, elevated liver enzymes, thrombocytopenia, symptoms) remain detectable 6
• Do not abruptly discontinue antihypertensives postpartum; use gradual tapering approach 9, 2
• Recognize that preeclampsia may worsen or appear for the first time after delivery, particularly in the first 1-2 weeks postpartum 6