Is propranolol (beta blocker) safe to use during pregnancy?

Propranolol Use During Pregnancy

Propranolol should be avoided during the first trimester if possible, but can be used during the second and third trimesters with careful monitoring of fetal growth and preparation for potential neonatal complications. 1, 2

Safety Classification and Recommendations

• Propranolol is classified as Pregnancy Category C by the FDA 3
• The European Society of Cardiology recommends propranolol as an option for managing cardiac conditions during pregnancy, particularly for:
  • Long-term management of idiopathic sustained ventricular tachycardia (Class I recommendation)
  • Management of congenital long QT syndrome during pregnancy and postpartum 2
• The American Heart Association and ACC/AHA/ESC guidelines indicate propranolol is generally considered safe but should be avoided in the first trimester when possible 1, 2

Potential Risks to the Fetus/Neonate

• Intrauterine growth restriction (IUGR) is the most consistently reported adverse effect 1, 3, 4
• Potential neonatal complications include:
  • Bradycardia
  • Hypoglycemia
  • Respiratory depression
  • Small placenta size 3

Monitoring Recommendations

• Regular ultrasound monitoring of fetal growth is essential throughout pregnancy 2
• Facilities for monitoring neonates at birth should be available due to potential complications 2, 3
• If used for hypertension management, blood pressure should be closely monitored as pregnancy may alter drug effect even without changing pharmacokinetics 5

Clinical Considerations

• Beta-blockers with selective β1 properties (like metoprolol) are theoretically preferable to propranolol (non-selective) because they may interfere less with peripheral vasodilatation and uterine relaxation 1
• For cardiac indications where propranolol is specifically indicated, the benefits may outweigh the risks, particularly after the first trimester
• Propranolol is excreted in human milk, so caution should be exercised during breastfeeding 3

Comparative Evidence

The evidence regarding propranolol use in pregnancy shows some contradictions:

• Some older studies report significant concerns about fetal outcomes, particularly in hypertensive pregnancies 6, 7
• Other research suggests improved outcomes when propranolol is used to manage severe hypertension in pregnancy 8
• More recent guidelines suggest propranolol can be used with appropriate monitoring, especially after the first trimester 1, 2

Clinical Decision Algorithm

1. First trimester: Avoid propranolol if possible; consider alternative medications
2. Second/third trimesters: If propranolol is indicated:
   • Use the lowest effective dose
   • Monitor fetal growth with regular ultrasounds
   • Prepare for potential neonatal complications at delivery
   • Consider β1-selective alternatives (metoprolol) if appropriate for the condition
3. Delivery planning: Ensure facilities are available for monitoring potential neonatal complications (bradycardia, hypoglycemia, respiratory depression)

Remember that maternal benefit must be weighed against potential fetal risks, particularly for serious cardiac conditions where propranolol may be specifically indicated.