Summary:

Severe hypertension can be a life-threatening event during pregnancy and requires special vigilance in the postpartum period, particularly following hospital discharge. The goal of treatment is to control hypertension and prevent seizures.  Uncontrolled hypertension can lead to heart failure, myocardial ischemia, renal injury and stroke.

When to Treat:

Urgently treat acute onset severe hypertension in pregnancy or postpartum period

• SBP ≥160 and and/or DBP ≥110 mm Hg persisting for 15 minutes
  • systolic BP a predictor of maternal morbidity/mortality

First Line Therapy:

Nifedipine

Hydralazine

Labetalol

Immediate Release Oral Nifedipine

Onset

• 5 to 10 minutes

Administration

• 10 to 20 mg orally
• Repeat in 20 minutes if needed
• Then 10 to 20 mg every 2 to 6 hours
• Maximum dose: 180 mg

Medication Risks

• Maternal tachycardia and headaches

IV Hydralazine

Onset

• 10 to 20 minutes

Administration

• IV
  • 5  to 10 mg IV (or IM)
  • Then 5 to 10 mg IV every 20 to 40 minutes
• Infusion
  • 0.5 to 10 mg/hr
• Maximum dose: 20 mg

Medication Risks 

• Maternal hypotension and headaches
• Abnormal FH tracings

IV Labetalol

Onset

• 1 to 2 minutes

Administration 

• IV
  • 10 to 20 mg IV
  • Then 20 to 80 mg every 10 to 30 minutes
• Infusion
  • 1 to 2 mg/min
• Maximum dose: 300 mg

Medication Risks 

• Avoid in the following clinical settings
  • Asthma
  • Preexisting myocardial disease | Decompensated cardiac function | Heart block | Bradycardia

Note: ACOG states that “any of these agents can be used to treat acute severe hypertension in pregnancy” | An approach detailed in ACOG guidance uses “an initial regimen of labetalol at 200 mg orally every 12 hours and increase the dose up to 800 mg orally every 8–12 hours as needed (maximum total 2,400 mg/d). If the maximum dose is inadequate to achieve the desired blood pressure goal, or the dosage is limited by adverse effect, then short-acting oral nifedipine can be added gradually”

Seizure Prophylaxis: Magnesium Sulfate

• Remains drug of choice for seizure prophylaxis
• Magnesium sulfate should not be used to reduce blood pressure
• See more on magnesium sulfate in ‘Related ObG Topics’

When to Use

• Severe features of preeclampsia
  • Administer to all women
• No severe features of preeclampsia and systolic BP > 140 and < 160 mm Hg or diastolic BP > 90 and < 110 mm Hg
  • There is no consensus on this matter as prophylaxis will reduce eclampsia but 1 in 100 to 129 women need to be treated and side effects (although not life threatening) will increase
  • ACOG states that the decision to use magnesium sulfate when severe features are not present should be the decision of the “physician or institution, considering patient values or preferences, and the unique risk-benefit trade-off of each strategy”

Delivery and Postpartum

• Vaginal delivery
  • Continue infusion 24 hours postpartum
• Cesarean
  • Begin infusion (if not yet running) before surgery and continue 24 hours postpartum
  • Discontinuing prior to operative vaginal birth or cesarean section to avoid uterine atony or anesthetic drug interactions is not recommended

Administration

• Loading dose of 4 to 6 g administered per infusion pump over 20 to 30 minutes (i.e., slowly) followed by a maintenance dose of 1 to 2 g per hour as a continuous intravenous infusion
• IM option if IV access limited
  • 10 g initially as a loading dose (5 g IM in each buttock) followed by 5 g every 4 hours
  • Mix with 1 mL xylocaine 2% to alleviate pain

Learn More – Primary Sources:

ACOG Practice Bulletin 222: Gestational Hypertension and Preeclampsia

ACOG II Severe Hypertension in Pregnancy Bundle

FIGO: A literature review and best practice advice for second and third trimester risk stratification, monitoring, and management of pre-eclampsia

Related ObG Topics:

Diagnosing Preeclampsia – Key Definitions and ACOG Guidelines

Aspirin Treatment for Women at Risk for Preeclampsia – ACOG, SMFM and USPSTF Recommendations

Does Enoxaparin Prevent Preeclampsia?

ASPRE Trial: A Combined Risk Algorithm and Use of Aspirin to Prevent Preterm Preeclampsia

Eclampsia and Role of Magnesium Sulfate