Can aspirin (acetylsalicylic acid) cause vaginal spotting?

Aspirin and Vaginal Spotting

Yes, aspirin can cause vaginal spotting due to its antiplatelet effects that increase the risk of bleeding events, including vaginal bleeding. 1 This is consistent with aspirin's well-documented ability to increase the risk of bleeding throughout the body.

Mechanism and Risk Factors

Aspirin causes bleeding through its antiplatelet effects, which inhibit blood clotting. The risk of aspirin-induced bleeding, including vaginal spotting, is:

• Dose-dependent: Higher doses of aspirin are associated with greater bleeding risk 1, 2, 3

  • Low-dose aspirin (75-100mg/day) increases overall bleeding risk with a relative risk of 1.4 (95% CI: 1.2-1.7) 4
  • Women taking 6-14 standard tablets/week have a 1.77-fold increased risk of bleeding compared to non-users 3
  • Women taking >14 tablets/week have a 2.24-fold increased risk 3

• Affected by concurrent medications:

  • Risk increases significantly when aspirin is combined with:
    • NSAIDs
    • Anticoagulants (with a pooled odds ratio of 1.36-1.42) 5
    • Selective serotonin reuptake inhibitors 1
  • Proton pump inhibitors may decrease upper GI bleeding risk but don't affect vaginal bleeding 1

• Age-related: Bleeding risk increases with age, with an estimated adjusted incidence rate ratio of 1.05 for each increasing year 6

Clinical Approach to Aspirin-Related Vaginal Spotting

When evaluating vaginal spotting in a woman taking aspirin:

1. Rule out other gynecological causes of spotting first, including:

   • Hormonal imbalances
   • Structural abnormalities
   • Pregnancy complications
   • Infections 1

2. If aspirin is determined to be the cause:

   • Consider reducing the aspirin dose if clinically appropriate, as bleeding risk is dose-dependent 1, 2, 3
   • For primary prevention in low-risk individuals, consider discontinuation after discussing risks and benefits 1
   • For secondary prevention of cardiovascular disease, the benefits may outweigh the risk of spotting 1

Important Considerations

• Aspirin's effect on vaginal bleeding may be more pronounced in women with underlying bleeding disorders 1

• Contrary to common belief, the duration of aspirin use does not significantly increase bleeding risk after controlling for dose:

  • Studies in both men and women show that after adjusting for dose, increasing duration of use was not associated with greater bleeding risk (P trend = 0.28 in women, P trend = 0.749 in men) 2, 3
  • This suggests that if a woman tolerates a specific dose of aspirin without spotting initially, she is unlikely to develop this side effect later if the dose remains constant

• Small doses of aspirin (2 × 325 mg tablets every 4 hours for 24 hours) do not appear to significantly alter menstrual blood loss patterns in studies specifically examining menstruation 7

• Contraindication: Tranexamic acid, sometimes used to treat heavy menstrual bleeding, is contraindicated in women taking aspirin due to thrombosis risk 1

For women experiencing aspirin-induced vaginal spotting who require continued aspirin therapy, the optimal approach is to use the lowest effective dose that balances cardiovascular protection with bleeding risk.