Deep vein thrombosis: DVT and PE were rare in pregnancy

Clinical bottom line (level 2c)

  1. Women during pregnancy and the puerperium were at increased risk for venous thromboembolism, but it was rare
McColl et al: Thromb Hamost 1997; 78: 1183-1188
Expires August 2003

The study

Retrospective cohort study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: 2 maternity hospitals, Scotland

72201 patients (aged <49 years, 100% female) venous thromboembolic disease in pregnancy or the puerperium (<6 wk post-partum). Patients with confirmed DVT/PE were invited for interview and blood screening to define risk factors.

Excluded if
  • aged >49y


    • Patients with suspected DVT had ultrasound or venography, patients with suspected PE had ventilation-perfusion scanning


    Outcomes studied:
  • DVT in pregnancy and puerperium (Incidence per 1000)
  • PE in pregnancy and puerperium (Incidence per 1000)

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    DVT in pregnancy and puerperium ? / 0.71%
    (0.50% to 0.90%)
    PE in pregnancy and puerperium ? / 0.15%
    (0.06% to 0.24%)

    • For % read 'per thousand'
    • A risk factor (e.g. obesity/infection/major illness) was found in over half patients
      • 28% had no risk factors
      • 12% (95% CI: 3 to 21) had antithrombin III deficiency
      • 8% (95% CI: 0.5 to 16) had factor V Leiden

    Comments

    1. 19% of subjects were lost to follow-up; the estimates of prevalence of risk factors may be biased.

    Citation

    1. McColl MD, Ramsay JE, Tait RC, et al: Risk factors for pregnancy associated venous thromboembolism. Thromb Hamost 1997; 78: 1183-1188
    Contributor: Chris Ball and Bob Phillips, May 1998
    Reviewer: Paul Flynn

    Clinical Question.
    Patient not pre pregnant
    Intervention or Exposure pregnancy
    Outcome venous thromboembolism; DVT; PE