What are the hallmark signs and symptoms of preeclampsia, at what gestational age do they typically occur, and what diagnostic tests and follow-up recommendations are indicated?

Hallmark Signs, Symptoms, and Management of Preeclampsia

Preeclampsia is characterized by new-onset hypertension (≥140/90 mmHg) that appears after 20 weeks of gestation, accompanied by proteinuria or evidence of maternal organ dysfunction or uteroplacental dysfunction. 1, 2

Diagnostic Criteria and Timing

Key Diagnostic Features

• New hypertension (≥140/90 mmHg) occurring after 20 weeks of gestation in previously normotensive women 1, 3
• Proteinuria (>0.3 g/24h or albumin-creatinine ratio ≥30 mg/mmol or ≥1+ on dipstick) 1, 3
• In the absence of proteinuria, diagnosis requires hypertension plus at least one sign of maternal organ dysfunction 3, 2

Timing of Onset

• Preeclampsia develops after 20 weeks of gestation (by definition) 4, 5
• Serious morbidity can occur from 20 weeks' gestation to after delivery 3
• Early-onset preeclampsia (<34 weeks) has worse outcomes and is associated with placental abnormalities 6
• Late-onset preeclampsia (>34 weeks) is more common, with eclampsia most common at term 3, 6
• Onset before 32 weeks has the most serious outcome with an average interval between diagnosis and delivery of 14 days (range 0-62 days) 3

Signs and Symptoms

Maternal Symptoms

• Headache (new onset, persistent) 3, 1
• Visual disturbances (blurred vision, flashing lights, scotomata) 3, 1
• Epigastric or right upper quadrant pain 3, 2
• Nausea or vomiting 3
• Shortness of breath (pulmonary edema) 3, 2

Clinical Signs

• Hypertension (≥140/90 mmHg) 1, 2
• Severe hypertension (≥160/110 mmHg) requires immediate treatment 1, 2
• Proteinuria (present in approximately 75% of cases) 3, 1
• Excessive edema (though not a diagnostic criterion) 2
• Hyperreflexia (though no longer recommended as a diagnostic criterion) 3, 1

Evidence of Maternal Organ Dysfunction

• Renal dysfunction: serum creatinine ≥1.1 mg/dL or doubling of baseline 1
• Liver dysfunction: elevated transaminases ≥2 times upper limit of normal 1, 2
• Hematological abnormalities: thrombocytopenia (<100,000/microliter) 1, 2
• Neurological complications: severe headache, visual disturbances, eclampsia 3, 1
• Pulmonary edema 3, 2

Fetal Manifestations

• Fetal growth restriction 3, 1
• Abnormal umbilical artery Doppler waveform 3
• Reduced fetal movements 3
• Small for gestational age infant 3

Diagnostic Tests

Initial Assessment

• Blood pressure measurement (using proper technique to avoid errors) 3
• Urinalysis with protein quantification (dipstick, protein/creatinine ratio, or 24-hour collection) 1
• Full blood count (hemoglobin and platelet count) 3, 1
• Liver function tests (AST, ALT, LDH) 3, 1
• Renal function tests (serum creatinine, electrolytes, uric acid) 3, 1
• Coagulation studies if thrombocytopenia is present 1

Additional Tests

• Fetal assessment: ultrasound for growth, amniotic fluid volume, and umbilical artery Doppler 3, 1
• sFlt-1/PlGF ratio (≤38 can exclude development of preeclampsia in the following week) 1, 6
• Renal ultrasound if serum creatinine or urine testing is abnormal 3

Follow-up Recommendations

Management Based on Severity

• For new hypertension without proteinuria:

  • Diastolic BP ≥90 and <100 mmHg: refer for hospital assessment within 48 hours 3
  • Diastolic BP ≥90 and <100 mmHg with symptoms: same-day hospital assessment 3
  • Systolic BP ≥160 mmHg or diastolic BP ≥100 mmHg: same-day hospital assessment 3

• For new hypertension with proteinuria:

  • Diastolic BP ≥90 mmHg and new proteinuria ≥1+: same-day hospital assessment 3
  • Diastolic BP ≥110 mmHg or systolic BP ≥170 mmHg with proteinuria: immediate admission 3
  • Any proteinuria with symptoms: immediate admission 3

• For new proteinuria without hypertension:

  • 1+ proteinuria: repeat assessment within one week 3
  • ≥2+ proteinuria: hospital assessment within 48 hours 3
  • Any proteinuria with symptoms: same-day hospital assessment 3

Monitoring Frequency

• Women with no risk factors: follow local protocols and NICE guidelines (typically assessments at weeks 16,28,34,36,38,40, and 41) 3
• Women with one risk factor: assessments at least every three weeks before 32 weeks, then at least every two weeks until delivery 3
• Women with two or more risk factors: early specialist referral for individualized assessment 3

Patient Education

• All pregnant women should be informed about symptoms of preeclampsia 3
• Women should know how to contact healthcare professionals at all times 3
• Women should understand that preeclampsia can develop between scheduled antenatal assessments 3

Important Considerations and Pitfalls

• Proper blood pressure measurement technique is critical; errors have been implicated in maternal deaths 3
• Preeclampsia can progress rapidly to life-threatening complications within approximately two weeks from diagnosis 3
• Neither serum uric acid nor the level of proteinuria should be used to determine timing of delivery 1
• Hyperreflexia is nonspecific and no longer recommended as a diagnostic criterion 3
• Headaches in pregnancy are multifactorial, but new headache with hypertension should be considered preeclampsia until proven otherwise 3
• HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) represents a severe manifestation of preeclampsia 3, 2
• The only definitive treatment for preeclampsia is delivery of the placenta 2, 5