BACKGROUND AND PURPOSE:

• Cesarean section is believed to be linked to greater risk for postpartum venous thromboembolism (VTE)
• There is conflicting data, especially around the issue of emergency vs scheduled surgeries
• Blondon et al. (CHEST Journal, 2016) sought to identify the risk of VTE and associated risk factors following cesarean section compared to vaginal delivery

METHODS:

• Systematic review and meta-analysis
• Systematic review of 28 mostly retrospective observational studies and 32 prospective studies reporting risks of VTE following cesarean section
• Primary goal: Refine risk estimates of postpartum VTE following cesarean section, compared to vaginal delivery (both unadjusted and multiadjusted analyses)
• Secondary goal: Provide meta-analytic summary estimate of incidence of postpartum VTE following cesarean section

RESULTS:

• Mean age of women 25-30 years
  • BMI and thromboprophylaxis data often lacking
  • Majority of women were white but some studies were more diverse
• Risk of VTE following cesarean section when analyzing individual studies ranged from 1 to 22 times that of vaginal delivery
  • Pooled OR 3.7 (95% CI, 3.0-4.6)
  • Pooled OR 5.9 (95% CI, 3.9-9.1) when only including studies with objective VTE diagnoses
• Adjustment for age and BMI had a marginal influence on the estimated pooled OR
• Estimates of associations were stronger for emergency CS, compared to elective CS even after adjustments
  • Elective section: OR 2.1 (95% CI, 1.5-2.9)
  • Emergency section: OR, 2.8 (95% CI, 2.1-3.6)
• Based on prospective studies (32 studies; 120,603 women)
  • The pooled incidence was 2.6 VTE per 1,000 sections (95% CI, 1.7-3.5) and was greater in studies with a longer and better follow-up in the postpartum period (4.3 per 1,000 sections)
  • Mean age: 30 years
  • Mean BMI: 25 kg/m²

CONCLUSION:

• VTE risk was approximately fourfold greater following cesarean section compared to vaginal delivery
• Risk was greater following emergency vs elective section
• Approximately 3 in 1,000 women will develop a VTE following cesarean section

Learn More – Primary Sources:

Risks of Venous Thromboembolism After Cesarean Sections: A Meta-Analysis

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