## Management of Hypertension in Pregnancy ### Key Principle **Key Point:** ACE inhibitors (including enalapril) are **contraindicated throughout pregnancy**, particularly in the second and third trimesters, due to the risk of fetal renal dysgenesis, oligohydramnios, intrauterine growth restriction (IUGR), and fetal death. Enalapril must be stopped immediately and replaced with a pregnancy-safe antihypertensive. ### Drugs Safe in Pregnancy for Hypertension | Drug Class | Examples | Trimester Safety | Notes | |---|---|---|---| | **First-line agents** | Methyldopa, Labetalol, Nifedipine (ER) | All trimesters | Proven safety record; preferred in pregnancy | | **ACE inhibitors** | Enalapril, Lisinopril | **CONTRAINDICATED** | Teratogenic in 2nd/3rd trimester | | **ARBs** | Losartan, Valsartan | **CONTRAINDICATED** | Similar risk to ACE inhibitors | | **Diuretics** | Hydrochlorothiazide | Caution | May reduce placental perfusion; avoid if possible | | **Beta-blockers** | Labetalol | Safe | Preferred beta-blocker; atenolol associated with IUGR | | **Hydralazine** | — | Safe (2nd/3rd trimester) | Used as add-on; not monotherapy | ### Why Methyldopa + Nifedipine (Extended-Release)? 1. **Methyldopa** is a centrally acting alpha-2 agonist with the longest safety record in pregnancy. It is the **most widely recommended first-line agent** for chronic hypertension in pregnancy per WHO, NICE, and ACOG guidelines (KD Tripathi, 8th ed.; Harrison's Principles of Internal Medicine, 21st ed.). 2. **Nifedipine (extended-release)** is a dihydropyridine calcium channel blocker — safe in all trimesters, effective for moderate-to-severe hypertension, and guideline-endorsed as a first-line or add-on agent in pregnancy. 3. The combination of **methyldopa + nifedipine ER** is the **classic, guideline-recommended regimen** for chronic hypertension in pregnancy when monotherapy is insufficient, and is the most commonly tested combination in NEET PG / INI-CET. **High-Yield:** The standard first-line regimen for chronic hypertension in pregnancy is **methyldopa ± nifedipine (ER)**. Labetalol is an acceptable alternative, but hydralazine is generally reserved as a third-line add-on or for acute hypertensive emergencies — not as a routine second agent in a stable outpatient setting. ### Clinical Pearl **Clinical Pearl:** Enalapril must be stopped immediately upon confirmation of pregnancy. The combination of methyldopa + nifedipine ER is the most appropriate switch for a patient at 16 weeks with BP 160/105 mmHg requiring dual therapy. Hydralazine is not a preferred oral outpatient add-on agent; its use is primarily parenteral in hypertensive urgency/emergency in pregnancy. ### Why Not the Other Options? - **Option A (Continue enalapril + amlodipine):** Enalapril is absolutely contraindicated in pregnancy and must be discontinued immediately; continuing it in any form is unsafe. - **Option B (Labetalol + hydralazine):** While labetalol is safe in pregnancy, hydralazine is not a standard oral outpatient add-on agent — it is primarily used parenterally for acute hypertensive crises. Methyldopa + nifedipine ER is the more guideline-consistent oral combination for chronic management. - **Option D (Increase enalapril dose):** Enalapril is absolutely contraindicated; increasing the dose further worsens fetal risk (renal agenesis, oligohydramnios, fetal death). *Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.; ACOG Practice Bulletin No. 203; WHO Guidelines for the Management of Hypertensive Disorders of Pregnancy.*
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