What are the principles of antihypertensive therapy in preeclampsia?

Principles of Antihypertensive Therapy in Preeclampsia

The primary goal of antihypertensive therapy in preeclampsia is to reduce maternal risk of stroke by maintaining blood pressure below 160/110 mmHg, while balancing fetal safety. 1

Correct Principles of Antihypertensive Management

Blood Pressure Targets

• Target blood pressure should be <140/90 mmHg to reduce maternal stroke risk 1
• Severe hypertension (≥160/110 mmHg) requires immediate treatment to prevent maternal stroke, heart failure, and adverse fetal outcomes 1
• Rapid reduction of severely elevated blood pressure is necessary, but overly aggressive reduction should be avoided

Medication Selection

• First-line medications for preeclampsia include:
  • Labetalol (oral or IV)
  • Nifedipine (extended release)
  • Methyldopa 1
• Hydralazine is also commonly used for acute management of severe hypertension 1
• ACE inhibitors, ARBs, and direct renin inhibitors are contraindicated during pregnancy due to fetotoxicity 1

Prevention and Monitoring

• Close maternal and fetal surveillance is essential during treatment 1
• Blood pressure should be monitored every 4 hours during hospitalization 2
• Delivery is the definitive treatment for preeclampsia when maternal condition worsens or fetal distress occurs 1

Common Misconceptions (Addressing Options in Question)

1. Using ASA 81 mg daily: While low-dose aspirin has a role in preventing preeclampsia in high-risk women, it is not a treatment for established preeclampsia. The Cochrane review showed only a 15% reduction in preeclampsia incidence with aspirin prophylaxis 1.

2. Reducing maternal risk of stroke: This IS a correct principle - antihypertensive therapy in preeclampsia aims to reduce the risk of maternal stroke by controlling blood pressure 1.

3. Rapid reduction of DBP to <80 mmHg: This is INCORRECT and potentially dangerous. Overly aggressive blood pressure reduction can compromise uteroplacental perfusion. The target is <140/90 mmHg, not <80 mmHg 1.

4. Bringing DBP to first prenatal visit level: This is not an established principle. Treatment aims for specific targets (<140/90 mmHg) rather than returning to baseline levels 1.

Evidence for Antihypertensive Benefits

• Antihypertensive treatment reduces progression to severe hypertension by 50% compared to placebo 1
• A retrospective study of 239,454 patients with preeclampsia showed that increased use of antihypertensive medications correlated with a >50% reduction in stroke during delivery hospitalizations 3
• The risk of stroke decreased from 13.5 per 10,000 deliveries in 2006-2008 to 6.0 in 2012-2014 as antihypertensive use increased 3

Pitfalls to Avoid

• Overly aggressive blood pressure reduction can compromise uteroplacental perfusion
• Failure to recognize that preeclampsia can develop or worsen postpartum 2
• Delaying treatment of severe hypertension increases risk of maternal stroke
• Not recognizing that preeclampsia requires more than just blood pressure management - it's a systemic disorder of endothelial dysfunction 4

Remember that while controlling blood pressure is important, delivery remains the only definitive treatment for preeclampsia when maternal or fetal status deteriorates 1.