What are the differences between gestational hypertension, preeclampsia, and eclampsia?

Differences Between Gestational Hypertension, Preeclampsia, and Eclampsia

Gestational hypertension is isolated new-onset hypertension after 20 weeks without organ dysfunction, preeclampsia adds end-organ damage or proteinuria to this hypertension, and eclampsia is preeclampsia complicated by seizures. 1

Gestational Hypertension

Definition: Persistent new-onset hypertension (BP ≥140/90 mm Hg) developing at or after 20 weeks' gestation without any features of preeclampsia 1.

Key Clinical Points:

• This is not a benign condition—approximately 25% of cases will progress to preeclampsia 1
• Risk of progression is highest when diagnosed before 34 weeks 1
• No proteinuria or evidence of maternal organ dysfunction
• Requires close monitoring throughout pregnancy with urinalysis at each visit and laboratory testing (complete blood count, liver enzymes, creatinine, uric acid) at minimum at 28 and 34 weeks 1

Management Threshold:

• Hospital assessment required if BP reaches ≥160/110 mm Hg or if preeclampsia develops 1
• Optimal delivery timing is 38-39 weeks if no progression occurs 1

Preeclampsia

Definition: Gestational hypertension (BP ≥140/90 mm Hg after 20 weeks) plus one or more of the following new-onset conditions 1:

• Proteinuria (≥0.3 g/24 hours or protein/creatinine ratio ≥30 mg/mmol)
• Maternal organ dysfunction:
  • Renal insufficiency (creatinine >90 μmol/L)
  • Liver involvement (elevated transaminases with or without right upper quadrant/epigastric pain)
  • Neurological complications (severe headache unresponsive to medication, visual disturbances, stroke)
  • Hematological complications (thrombocytopenia <150,000/μL, disseminated intravascular coagulation, hemolysis)
• Uteroplacental dysfunction (fetal growth restriction)

Critical Distinction: Proteinuria is present in approximately 75% of cases but is not required for diagnosis if other organ dysfunction is present 1.

Severe Features Requiring Immediate Action:

• BP ≥160/110 mm Hg
• Proteinuria with severe hypertension
• Neurological signs or symptoms
• HELLP syndrome (hemolysis, elevated liver enzymes, low platelets)

Management:

• All women require hospital assessment at initial diagnosis 1
• Women with severe features need magnesium sulfate for seizure prophylaxis 2, 1
• Delivery is definitive treatment, particularly at ≥34 weeks with severe features 2
• Between 34-36+6 weeks without severe features: expectant management is reasonable 2
• At ≥37 weeks: delivery is recommended to reduce maternal morbidity 2

Eclampsia

Definition: The occurrence of seizures in a woman with preeclampsia that cannot be attributed to other causes 1.

Key Features:

• Represents the most severe manifestation of the preeclampsia spectrum
• Can occur antepartum, intrapartum, or postpartum
• Requires immediate treatment with intravenous magnesium sulfate 1

Standard Magnesium Sulfate Protocol:

• Loading dose: 4 g IV or 10 g IM
• Maintenance: 5 g IM every 4 hours OR 1 g/hour infusion
• Continue until delivery and for at least 24 hours postpartum 1

Blood Pressure Treatment Thresholds

Critical Distinction in Management:

• Severe hypertension (≥160/110 mm Hg): Requires urgent treatment in a monitored setting regardless of diagnosis (gestational hypertension, preeclampsia, or chronic hypertension) using oral nifedipine or IV labetalol/hydralazine 1

• Non-severe hypertension (140-159/90-109 mm Hg):

  • For chronic hypertension: ACOG recommends treatment threshold of ≥140/90 mm Hg 2
  • For gestational hypertension and preeclampsia: ACOG recommends acute treatment only at ≥160/110 mm Hg, though ISSHP recommends treatment at ≥140/90 mm Hg 2, 1
  • Target diastolic BP of 85 mm Hg when treating 1

Common Pitfalls to Avoid

1. Assuming gestational hypertension is benign—it carries significant risk of progression and requires vigilant monitoring 1

2. Requiring proteinuria for preeclampsia diagnosis—approximately 25% of preeclampsia cases lack proteinuria but have other organ dysfunction 1

3. Delaying magnesium sulfate in preeclampsia with severe features—this is essential for seizure prophylaxis 2, 1

4. Missing postpartum presentations—hypertensive disorders can worsen or initially present after delivery and account for up to 44% of pregnancy-related deaths in the first 6 days postpartum 3

5. Failing to recognize the progression sequence—women can transition from gestational hypertension → preeclampsia → eclampsia, requiring escalating levels of intervention at each stage