A 28-year-old primigravida at 32 weeks of gestation presents with blood pressure 158/102 mmHg, proteinuria 2+ on dipstick, and hyperreflexia. She has no symptoms of imminent eclampsia. What is the drug of choice for antihypertensive therapy in this patient?

Explanation

## First-Line Antihypertensive in Pregnancy-Induced Hypertension **Key Point:** Labetalol is the first-line oral antihypertensive agent for chronic management of pregnancy-induced hypertension (PIH) and preeclampsia in the second and third trimesters. ### Mechanism & Safety Profile Labetalol is a combined α- and β-adrenergic antagonist that: - Reduces systemic vascular resistance without reflex tachycardia - Maintains uteroplacental perfusion (does not cause fetal hypoxia) - Has extensive safety data in pregnancy with no teratogenic effects - Achieves BP control within 2–4 hours of oral dosing ### Comparison of Antihypertensives in Pregnancy | Drug | Trimester Safety | Mechanism | Use in PIH | Notes | |------|------------------|-----------|-----------|-------| | **Labetalol** | Safe all trimesters | α/β-blocker | First-line oral | Preferred for chronic management | | **Methyldopa** | Safe all trimesters | Central α-agonist | Second-line oral | Slower onset; used historically | | **Nifedipine (ER)** | Safe all trimesters | CCB | First-line alternative | For acute/chronic control | | **Atenolol** | Avoid (IUGR risk) | β-blocker (selective) | Contraindicated | Associated with fetal growth restriction | | **ACE inhibitors** | Contraindicated 2nd/3rd | Renal vasodilator | Avoid | Fetal renal dysgenesis, oligohydramnios | | **Diuretics** | Avoid (↓ plasma volume) | Volume depletion | Avoid | Worsens placental perfusion | **High-Yield:** In Indian guidelines (FOGSI, ICOG), labetalol and nifedipine are the two first-line agents for PIH; methyldopa is reserved as a second-line option due to slower onset and lower efficacy. ### Clinical Pearl Labetalol is particularly useful in this patient because: - She is at 32 weeks (safe in 2nd/3rd trimester) - She has preeclampsia features (proteinuria + hyperreflexia) - Oral formulation allows outpatient management if not in labor - No adverse fetal effects even with prolonged use **Tip:** Remember the mnemonic **LMNOP** for safe antihypertensives in pregnancy: - **L**abetalol - **M**ethyldopa - **N**ifedipine - **O**ther (hydralazine — IV only, for acute crisis) - **P**razosin (rarely used) [cite:FOGSI Guidelines on Hypertension in Pregnancy], [cite:Harrison 21e Ch 427]