What is the management approach for a patient with hypertension in pregnancy?

Management of Hypertension in Pregnancy

The management of hypertension in pregnancy should include blood pressure control targeting <140/90 mmHg (but not below 80 mmHg diastolic) using first-line medications such as methyldopa, labetalol, or nifedipine, along with close monitoring for development of preeclampsia and fetal growth. 1, 2

Classification of Hypertensive Disorders in Pregnancy

Hypertension in pregnancy is classified into four categories:

1. Pre-existing (chronic) hypertension - Present before pregnancy or diagnosed before 20 weeks gestation
2. Gestational hypertension - New onset hypertension after 20 weeks without proteinuria
3. Preeclampsia - Hypertension with proteinuria or other maternal organ dysfunction
4. Pre-existing hypertension with superimposed gestational hypertension with proteinuria 1, 2

Diagnosis is confirmed when systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg, measured on at least two separate occasions or at least 15 minutes apart in severe hypertension (≥160/110 mmHg) 1.

Treatment Approach

Blood Pressure Thresholds for Treatment

• Start antihypertensive treatment when BP is ≥140/90 mmHg in women with:

  • Gestational hypertension (with or without proteinuria)
  • Pre-existing hypertension with superimposed gestational hypertension
  • Hypertension with organ damage or symptoms 1, 2

• Target BP levels: <140/90 mmHg but not below 80 mmHg for diastolic BP 1, 2

Severe Hypertension Management

• BP ≥160/110 mmHg is considered a medical emergency requiring immediate treatment in a monitored setting 1, 2
• First-line options for severe hypertension:
  • IV labetalol
  • Oral nifedipine
  • IV hydralazine 2

Pharmacological Management

First-Line Medications

1. Methyldopa

   • Traditional first-line agent
   • Safe during pregnancy and breastfeeding
   • Dosage: 250-500 mg divided twice daily or more frequently 2, 3

2. Labetalol

   • Combined alpha and beta-blocker
   • Effective alternative to methyldopa
   • Dosage: 200-800 mg divided twice daily or more frequently 2, 4

3. Dihydropyridine Calcium Channel Blockers

   • Particularly nifedipine (extended-release preferred)
   • Dosage: 30-60 mg once daily 2

Contraindicated Medications

• ACE inhibitors and ARBs - Absolutely contraindicated due to risk of fetal toxicity and death 2
• Direct renin inhibitors - Contraindicated 2
• Diuretics - Use with caution, not first-line agents 2
• Atenolol - Use with caution due to reports of intrauterine growth retardation 2

Monitoring and Follow-up

Maternal Monitoring

• Regular BP measurements
• Urinalysis at each visit to detect proteinuria
• Blood tests (hemoglobin, platelet count, liver enzymes, uric acid, creatinine) at minimum at 28 and 34 weeks 1
• Assessment for symptoms of preeclampsia (headache, visual disturbances, epigastric pain)

Fetal Monitoring

• Ultrasound from 26 weeks' gestation
• Follow-up every 2-4 weeks if fetal growth is normal
• More frequent monitoring if fetal growth restriction is suspected 1

Postpartum Management

• Continue monitoring BP for 24-72 hours postpartum as hypertension may worsen between days 3-6
• Review within 1 week if antihypertensives are still required at discharge 2
• Antihypertensive medications safe during breastfeeding include labetalol, nifedipine, enalapril, and metoprolol 1

Delivery Considerations

• For gestational hypertension without complications, delivery can be delayed until 39+6 weeks provided BP is controlled, fetal monitoring is reassuring, and preeclampsia has not developed 1
• For preeclampsia, delivery timing depends on severity, gestational age, and maternal/fetal condition

Long-term Cardiovascular Risk

• Women with history of hypertensive disorders in pregnancy have increased risk of future cardiovascular disease
• Women with history of preeclampsia have nearly four times higher risk of developing arterial hypertension later in life 2
• Regular follow-up and cardiovascular risk assessment is recommended after pregnancy 2, 5

Multidisciplinary Approach

• Management should involve collaboration between obstetricians, maternal-fetal medicine specialists, and when needed, cardiologists
• Each unit should have a protocol for BP management and regular audit of associated pregnancy outcomes 2

By following these guidelines, healthcare providers can effectively manage hypertension in pregnancy to reduce maternal and fetal morbidity and mortality while also addressing long-term cardiovascular health risks.