Why Check Uric Acid in Preeclampsia
Serum uric acid should be measured in preeclampsia because elevated levels are associated with worse maternal and fetal outcomes, and it serves as a key component of the mandatory twice-weekly monitoring protocol to assess disease severity and guide clinical management.
Primary Rationale for Monitoring
The International Society for the Study of Hypertension in Pregnancy (ISSHP) explicitly recommends that maternal monitoring in preeclampsia must include twice weekly blood tests for uric acid, along with hemoglobin, platelet count, and tests of liver and renal function 1. This is not optional—it's part of the standard monitoring algorithm for all women with preeclampsia.
Key Clinical Functions
1. Risk Stratification and Prognostic Value
Uric acid serves as a prognostic marker rather than a diagnostic criterion:
- Elevated gestation-corrected uric acid levels are associated with worse maternal and fetal outcomes 1
- Higher levels correlate with severe preeclampsia, eclampsia, and HELLP syndrome 2
- Elevated uric acid predicts complications including hepatic dysfunction and preterm delivery 3
- Meta-analysis shows sensitivity of 67-83% and specificity of 48-71% for predicting adverse perinatal outcomes 2
2. Assessment of Renal Function
Uric acid elevation reflects:
- Decreased renal clearance due to preeclampsia-related kidney dysfunction
- Severity of systemic endothelial damage
- Among renal function markers, uric acid demonstrates the best diagnostic performance for preeclampsia (AUC = 0.837) 4
3. Monitoring Disease Progression
Serial measurements help identify:
- Progressive deterioration requiring delivery consideration
- Women who may develop severe complications
- Need for intensified fetal surveillance when uric acid is elevated 1
Critical Caveats
Important limitation: While uric acid must be monitored, neither serum uric acid nor proteinuria levels should be used as an indication for delivery 1. This is a common pitfall—the value guides assessment intensity but not delivery timing decisions.
Delivery decisions are based on:
- Gestational age ≥37 weeks
- Severe refractory hypertension
- Progressive thrombocytopenia
- Progressively abnormal liver or renal enzyme tests
- Pulmonary edema
- Neurological features
- Nonreassuring fetal status
Monitoring Algorithm
For all women with preeclampsia 1:
- Check uric acid at least twice weekly (minimum frequency)
- Repeat with any change in clinical status
- Combine with: hemoglobin, platelets, liver transaminases, creatinine
- When elevated, prompt detailed fetal growth assessment even in gestational hypertension 1
Baseline assessment: Women with chronic hypertension should have uric acid measured at first diagnosis to establish baseline for detecting superimposed preeclampsia 1.
Evidence Strength
The guideline recommendations are based on consistent observational evidence showing associations between elevated uric acid and adverse outcomes. Recent large studies confirm that elevated uric acid before 20 weeks increases preeclampsia risk (OR 1.38-2.14 for levels >240 µmol/L) 5, 6, and meta-analyses demonstrate its prognostic value for complications 7, 2.
Bottom line: Uric acid monitoring is mandatory in preeclampsia management—not for diagnosis or delivery timing, but for risk stratification, assessing disease severity, and determining the intensity of maternal-fetal surveillance needed.