What are the signs of preeclampsia?

Signs of Preeclampsia

Preeclampsia is diagnosed by new-onset hypertension (≥140/90 mmHg) after 20 weeks of gestation accompanied by either proteinuria (≥300 mg/24 hours) or evidence of maternal organ dysfunction, with specific warning signs that require immediate recognition to prevent maternal and fetal mortality. 1

Diagnostic Criteria

The fundamental signs that define preeclampsia include:

• Blood pressure ≥140/90 mmHg measured on two occasions at least 4 hours apart after 20 weeks of gestation in a previously normotensive woman 1
• Proteinuria ≥300 mg in 24-hour urine collection or protein-to-creatinine ratio ≥30 mg/mmol on random sample, or ≥1+ on dipstick testing 1
• Organ dysfunction in the absence of proteinuria: thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema, or cerebral/visual disturbances 2

Note that proteinuria is no longer absolutely required for diagnosis if other organ dysfunction is present, and edema is not part of diagnostic criteria as it occurs in 60% of normal pregnancies. 1

Signs of Severe Preeclampsia

These warning signs indicate progression to severe disease and require urgent intervention:

Neurological Signs

• Severe persistent headache unresponsive to usual analgesics, indicating cerebral edema 1
• Visual disturbances including blurred vision, scotomata, photophobia, or temporary blindness (occipital lobe involvement) 1
• Hyperreflexia and clonus indicating central nervous system irritability 1, 3
• Convulsions/seizures representing progression to eclampsia 1

Hepatic Signs

• Right upper quadrant or epigastric pain caused by liver capsule distension from hepatic edema and potential hemorrhage 1, 3
• Elevated liver enzymes (transaminases >2× normal) 4

Hematological Signs

• HELLP syndrome: hemolysis, elevated liver enzymes, and low platelet count (<100,000/μL) 1, 4
• Thrombocytopenia as an isolated finding 2

Cardiovascular Signs

• Severe hypertension (≥160/110 mmHg) requiring urgent treatment 5, 4
• Pulmonary edema indicating severe fluid shifts and cardiac strain 5, 4

Renal Signs

• Renal insufficiency with rising creatinine or decreasing urine output 2, 4
• Worsening proteinuria (though degree does not predict outcomes) 5

Fetal Signs

• Reduced fetal movements reported by the mother 1
• Fetal growth restriction or small-for-gestational-age infant on ultrasound 1
• Abnormal umbilical artery Doppler indicating uteroplacental dysfunction 2, 5

Common Pitfalls

Do not attempt to classify preeclampsia as "mild" versus "severe" clinically—all cases can rapidly progress to emergencies. 5 Any woman presenting with new-onset hypertension after 20 weeks should be evaluated for proteinuria and organ dysfunction immediately. 1

Blood pressure may appear falsely normal in early pregnancy due to physiological BP decline in the first trimester, masking pre-existing hypertension that later manifests as apparent "gestational" hypertension. 1

The absence of proteinuria does not exclude preeclampsia if other organ dysfunction is present—this represents an important update to diagnostic criteria. 2, 4

Neither the degree of proteinuria nor serum uric acid levels should guide delivery decisions, as they correlate poorly with outcomes. 5

Postpartum preeclampsia can occur up to 6 weeks (or rarely longer) after delivery, so continued vigilance is essential even after the pregnancy has ended. 3, 6