Mnemonics to remember Antihypertensives in pregnancy

Managing blood pressure during pregnancy is a delicate balancing act. You need medications that are effective for the mother but safe for the developing fetus. In the high-stakes environment of a medical exam or a busy clinic, remembering which drugs are the “go-tos” and which are “no-gos” is essential.

Here is a breakdown of the most common antihypertensives used in pregnancy, complete with easy-to-remember mnemonics.

Safe to Use: “Mothers Need Happy, Calm Pregnancies”

This mnemonic covers the primary agents listed as safe for treating hypertension in pregnancy .

• M — Methyldopa (Alpha-Methyldopa)
  • Role: This is often the primary choice. It is a prodrug converted to alpha-methyl norepinephrine in the brain, reducing adrenergic discharge .
  • Note: The sources state this drug is now “only used therapeutically” for hypertension during pregnancy .
• N — Nifedipine (Calcium Channel Blocker)
  • Role: A calcium channel blocker listed as safe for pregnancy .
  • Caveat: It must be stopped before labor because calcium channel blockers can weaken uterine contractions .
• H — Hydralazine
  • Role: A direct-acting vasodilator that releases nitric oxide .
  • Use: It is specifically indicated for hypertension in pregnancy and is also used in hypertensive emergencies like eclampsia .
• C — Clonidine & Cardioselective Beta-Blockers
  • Clonidine: A centrally acting agent listed as safe .
  • Cardioselective Beta-Blockers: Drugs like Atenolol and Metoprolol are safe, but the text notes they are used only if no other choice is available .
• P — Prazosin
  • Role: An alpha-adrenergic blocker listed as a safe option for pregnancy .

Note on Labetalol: While not in the primary “Safe” list in slide , Labetalol (an alpha + beta blocker) is explicitly mentioned as a drug used to lower blood pressure in eclampsia (a severe complication of pregnancy) .

Drugs to Avoid: “SAND”

These drugs are contraindicated because they pose significant risks to the fetus or the pregnancy mechanism itself .

• S — Sodium Nitroprusside
  • Risk: Generally avoided in pregnancy . It is metabolized into cyanide and nitric oxide, carrying a risk of toxicity .
• A — ACE Inhibitors
  • Risk: These are fetopathic. They can cause hypoplasia of organs (underdevelopment), growth retardation, and other structural defects in the fetus .
• N — Non-selective Beta-Blockers
  • Risk: Drugs like Propranolol can cause low birth weight, neonatal bradycardia (slow heart rate), and hypoglycemia (low blood sugar) in the newborn .
• D — Diuretics
  • Risk: These reduce plasma volume, which lowers uteroplacental circulation (blood flow to the placenta), increasing the risk of fetal death .

Analogy: Think of the pregnant mother’s circulation as a garden (the uterus) being watered by a hose (blood vessels).

• Safe Drugs (Methyldopa, Hydralazine): These are like adjusting the nozzle setting to a wider spray. They lower the pressure in the hose without cutting off the water supply to the garden.
• Unsafe Drugs (Diuretics): These are like turning down the faucet at the source. It lowers the pressure, but the garden (the fetus) stops getting enough water to survive.