A 28-year-old multigravida at 30 weeks of gestation is found to have a blood pressure of 150/95 mmHg on two occasions 4 hours apart. She denies headache, visual disturbances, or epigastric pain. Urine dipstick is negative for protein. Which investigation is most appropriate to confirm the diagnosis of gestational hypertension and assess for subclinical proteinuria?

Explanation

## Investigation of Choice in Gestational Hypertension **Key Point:** In a patient with new-onset hypertension in pregnancy without symptoms or proteinuria on dipstick, the most appropriate investigation is **24-hour urinary protein or spot urine protein-to-creatinine ratio (UPCR)** to confirm the absence of proteinuria and differentiate gestational hypertension from preeclampsia. ### Gestational Hypertension vs. Preeclampsia | Feature | Gestational Hypertension | Preeclampsia | |---------|--------------------------|---------------| | **BP elevation** | Yes (≥140/90 mmHg) | Yes (≥140/90 mmHg) | | **Proteinuria** | Absent | Present (≥0.3 g/24 hr) | | **Symptoms** | Absent | May be present (headache, epigastric pain, visual changes) | | **Timing** | After 20 weeks | After 20 weeks | | **Diagnosis** | Clinical + absence of proteinuria | Clinical + proteinuria | **High-Yield:** Dipstick proteinuria is insensitive (false-negative in 20–30% of cases). **Quantitative proteinuria (24-hour urine or UPCR) is the gold standard** to definitively exclude proteinuria and confirm gestational hypertension. ### Why 24-Hour Urine or UPCR? 1. **Dipstick is unreliable** — may be negative despite significant proteinuria (especially in dilute urine). 2. **UPCR is faster and more practical** — single spot urine sample, results in hours (vs. 24 hours for 24-hour collection). 3. **Cutoff for abnormal UPCR** — >0.19 mg/mg (or >0.19 g/g) suggests proteinuria; ≥0.3 g/24 hr equivalent confirms preeclampsia. 4. **Differentiates diagnoses** — absence of proteinuria = gestational hypertension; presence = preeclampsia. **Clinical Pearl:** In asymptomatic women with new hypertension, quantitative proteinuria is the single most important test to confirm gestational hypertension and avoid unnecessary interventions. ### Diagnostic Algorithm ```mermaid flowchart TD A[New hypertension in pregnancy]:::outcome --> B{Symptoms or dipstick proteinuria?}:::decision B -->|Yes| C[Suspect preeclampsia]:::urgent C --> D[Check serum creatinine, LFTs, CBC]:::action B -->|No| E[Suspect gestational hypertension]:::outcome E --> F[Quantitative proteinuria: 24-hr urine or UPCR]:::action F --> G{Proteinuria present?}:::decision G -->|Yes| H[Reclassify as preeclampsia]:::urgent G -->|No| I[Confirm gestational hypertension]:::outcome ``` **Mnemonic: QUANT** — **Q**uantitative proteinuria (24-hr or UPCR) is the **U**ltimate **A**ssay for **N**ew hypertension in pregnancy without symptoms; **T**rust it over dipstick. [cite:ACOG Practice Bulletin 202; Williams Obstetrics 26e Ch 34]