Is the progestin-only pill (POP) safer than combined oral contraceptives (COCs) for a patient with a history of aneurysm?

Progestin-Only Pills Are Safer for Patients with History of Aneurysm

For patients with a history of aneurysm, progestin-only pills (POPs) are significantly safer than combined oral contraceptives (COCs) due to their minimal risk of thromboembolism and should be recommended as the preferred hormonal contraceptive option. 1, 2

Thrombotic Risk Comparison

Combined Oral Contraceptives (COCs)

• Significantly increase risk of thromboembolism (2-3 fold higher risk of venous thromboembolism compared to non-users) 3, 4
• The risk of venous thromboembolism in healthy women taking COCs is approximately 3-6 times higher than baseline risk 2
• Estrogen component is primarily responsible for increased thrombotic risk 5
• Contraindicated in patients with thrombophilia or history of thrombotic events 2, 1

Progestin-Only Pills (POPs)

• No significant increase in thrombotic risk (relative risk 0.90,95% CI 0.57-1.45) 2, 1
• Do not contain estrogen, eliminating the main component responsible for thrombotic risk 5
• Specifically recommended for patients with increased thrombosis risk 2, 1
• FDA labeling notes that POPs do not contain estrogen and therefore do not carry the same cardiovascular risks as combined hormonal contraceptives 5

Contraceptive Options for Patients with Aneurysm History

First-Line Options (Safest)

1. Progestin-only pills (POPs)

   • No significant increase in thrombotic risk 2, 6
   • Suitable for patients with contraindications to estrogen 1
   • Main mechanism is thickening cervical mucus rather than inhibiting ovulation 2

2. Levonorgestrel IUD

   • Relative risk for VTE: 0.61 (95% CI 0.24-1.53) 2, 1
   • Highly effective (>99%) 1
   • Local hormone action with minimal systemic effects 1

3. Copper IUD

   • No hormones, no thrombotic risk 1
   • Highly effective (>99%) 1

Contraindicated Options

1. Combined hormonal contraceptives (pills, patches, rings)

   • Strongly contraindicated due to increased thrombotic risk 2
   • Transdermal patch results in even greater estrogen exposure than oral methods 2

2. Depot medroxyprogesterone acetate (DMPA)

   • Limited data suggest higher VTE risk (RR 2.67) compared to other progestin-only methods 2
   • Should be avoided in patients with increased thrombosis risk 1

Important Considerations When Using POPs

Effectiveness

• Slightly lower effectiveness than COCs with typical use (pregnancy rates of 3-8% per year) 2
• Requires strict adherence to timing (must be taken at the same time each day, within a 3-hour window) 1
• No pill-free interval required 1

Side Effects

• Irregular bleeding is common 5
• Possible delayed follicular atresia/ovarian cysts 5
• For bothersome bleeding, NSAIDs for 5-7 days may help 1

Drug Interactions

• Certain medications, particularly rifampin and rifabutin, may reduce effectiveness 1
• Consider backup contraception when taking interacting medications 1

Clinical Decision Algorithm

1. Assess thrombotic risk:

   • History of aneurysm indicates high thrombotic risk
   • Avoid all estrogen-containing contraceptives

2. Consider patient preferences:

   • Need for high effectiveness
   • Tolerance for side effects (especially irregular bleeding)
   • Ability to adhere to strict timing requirements

3. Recommend in order of preference:

   • Levonorgestrel IUD (highest effectiveness, lowest systemic effects)
   • Copper IUD (highest effectiveness, no hormones)
   • Progestin-only pills (if IUDs not desired)

4. If choosing POPs:

   • Counsel on strict adherence to timing
   • Consider backup contraception methods (condoms)
   • Schedule follow-up to assess tolerance and bleeding patterns

Conclusion

For patients with a history of aneurysm, the thrombotic risk associated with combined hormonal contraceptives makes progestin-only methods the clearly safer choice. While IUDs (both hormonal and non-hormonal) offer the highest effectiveness, progestin-only pills provide a safe oral option with no significant increase in thrombotic risk.