What medication can be used to raise the heart rate in a pregnant woman with bradycardia?

Medications to Raise Heart Rate in Pregnant Women with Bradycardia

For symptomatic bradycardia in pregnancy requiring pharmacologic intervention, atropine is the primary medication, though a temporary pacemaker is the definitive treatment and can be safely implanted at any stage of pregnancy using echocardiographic guidance. 1

Immediate Management Approach

When Pharmacologic Treatment is Indicated

• Atropine is the standard anticholinergic agent used to increase heart rate in acute symptomatic bradycardia during pregnancy 2
• Atropine at 0.05 mg/kg increases maternal heart rate by approximately 25% without changing maternal arterial pressure, fetal arterial pressure, or fetal heart rate 2
• Atropine crosses the placenta significantly (fetal/maternal ratio reaches 1.0 at 4 hours), but studies in pregnant ewes showed no adverse circulatory effects on the fetus despite complete placental transfer 2

Alternative Anticholinergic Option

• Glycopyrrolate (0.025 mg/kg) is an alternative that produces similar maternal heart rate increases (25%) with significantly less placental transfer compared to atropine (peak fetal/maternal ratio of only 0.13) 2
• Despite theoretical advantages of reduced placental transfer, glycopyrrolate shows no superiority over atropine in terms of fetal safety, as neither agent causes adverse fetal circulatory effects 2

Definitive Treatment for Persistent Symptomatic Bradycardia

Pacemaker Implantation

• A permanent pacemaker for symptomatic bradycardia can be safely implanted at any stage of pregnancy using echocardiographic guidance to avoid radiation exposure 1, 3
• Pacemaker implantation is the preferred definitive therapy when bradycardia causes significant symptoms or hemodynamic compromise 3
• Echo-guided implantation eliminates fetal radiation exposure while maintaining procedural safety 1

Critical Considerations and Monitoring

Hemodynamic Assessment

• Determine if bradycardia is causing hemodynamic instability, maternal symptoms (dizziness, syncope, fatigue), or signs of inadequate perfusion before initiating treatment 3
• Assess fetal well-being with continuous fetal heart rate monitoring, as maternal bradycardia can potentially compromise uteroplacental perfusion 1

Underlying Causes to Address

• Rule out reversible causes: electrolyte abnormalities (hyperkalemia, hypomagnesemia), hypothyroidism, medications (beta-blockers, calcium channel blockers, digoxin toxicity), or high-grade AV block 1
• Evaluate for structural heart disease with echocardiography if bradycardia is new-onset or unexplained 1

Important Caveats

Atropine Use in Pregnancy

• While atropine may cause fetal tachycardia and decreased beat-to-beat variability of fetal heart rate in some cases, these effects are generally not clinically significant 2
• The complete placental transfer of atropine should not deter its use when maternal bradycardia requires treatment, as fetal hemodynamic effects are minimal 2

When NOT to Treat

• Asymptomatic bradycardia without hemodynamic compromise does not require pharmacologic intervention 3
• Physiologic sinus bradycardia in well-conditioned pregnant women (athletes) is benign and requires only observation 1

Avoid These Agents

• Do not use sympathomimetic agents (epinephrine, dopamine) for bradycardia in pregnancy unless treating concurrent hypotension from septic shock, as these are vasopressors that can cause severe hypertension when combined with oxytocic drugs 4, 5
• Epinephrine and dopamine may cause fetal harm and should only be used for their specific indications (hypotension/shock), not for isolated bradycardia 4, 5

Treatment Algorithm

1. Assess hemodynamic stability and symptoms: If unstable or severely symptomatic, proceed immediately to step 2 3

2. For acute symptomatic bradycardia: Administer atropine 0.5-1 mg IV (can repeat every 3-5 minutes up to 3 mg total) while preparing for definitive therapy 2

3. For persistent symptomatic bradycardia: Arrange urgent pacemaker implantation using echo guidance 1, 3

4. Continuous monitoring: Maintain fetal heart rate monitoring and maternal hemodynamic assessment throughout treatment 1