DVT and pregnancy: LMWH appeared safe and effective to prevent DVT in high risk patients.

Clinical bottom line (level 4)

  1. Low molecular weight heparin did not appear to cross the placenta.
  2. LMWH appeared to be effective in women with previous miscarriages and a 'severe thrombophilic tendency' in preventing venous thromboembolism.
Melissari et al: Thrombosis and Haemostasis 1992; 68 (6): 652-656
Expires April 2003

The study

Inception cohort study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.
Setting: teaching hospital, UK

15 patients (aged ?, 100% female) pregnant women having therapeutic termination of pregnancy at 16 to 23 weeks
Note:
  • Paired maternal and foetal venous samples taken before and immediately after termination. Low molecular weight heparin levels were assessed by anti-FXa assay.


    • Control Group: (n = 8, 8 analysed): given nothing
    Experimental Group: (n = 7, 7 analysed): fragmin 5,000 units, 15 hours and 3 hours before termination

    100% followed for ?

    The evidence

  • No low molecular weight heparin was detected in the foetal blood.

    • Comments

    1. A case series of eleven pregnant women with previous miscarriages and a 'severe thrombophilic tendency' were also studied.
    2. They received fragmin during pregnancy and early post-partum- initially 2500 units increased to 5000 units. It was adjusted so anti-FXa levels were 0.1 to 0.25 U/ml.
    3. All patients had uneventful pregnancies without excessive bleeding.
    4. There was no apparent bone mineral loss (measurement of vertebrae and proximal femur using dual photon absorptiometry compared with age-matched controls).

    Citation

    1. Melissari E, Parker CJ, Wilson NV, et al: Use of low molecular weight heparin in pregnancy. Thrombosis and Haemostasis 1992; 68 (6): 652-656
    Contributor: Chris Ball and Clare Wotton, May 2000
    Reviewer:

    Clinical Question.
    Patient pregnant women
    Intervention or Exposure therapeutic termination
    Outcome LMWH in foetal blood