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Heparin for pregnant women with acquired or inherited thrombophilias

MC Walker, SE Ferguson, VM Allen.

DOI: 10.1002/14651858.CD003580

David K. Cundiff, MD

Date received: July 10, 2007

Authors’ conclusions

Implications for practice

There is no information from randomised trials which could influence current practice.

Implications for research

Further studies are required to evaluate the effect of heparin on pregnancy outcomes for women with a thrombophilia. Two randomised studies are currently ongoing and may provide additional information.

This review included no RCTs. Subsequent to the publication of this review, an anticoagulation RCT reported that pregnant women with thrombophilia showed no reduction in in vitro coagulation activation with dalteparin.¹ No clinical data were reported.

Two trials were ongoing at the time of publication of this review. One is now published and compared dalteparin (5,000 units/day until 20 weeks then 5,000 units q12h until 37 weeks or onset of labor) to no treatment.¹ Prophylaxis with dalteparin at doses used in this study did not reduce coagulation activation in high risk thrombophilic women during pregnancy. No clinical data have been reported.

Despite the lack of RCT evidence, opinion-based treatment guidelines for pregnant women with thrombophilia by the Royal College of Obstetricians and Gynaecologists and the American College of Chest Physicians include giving thromboprophylaxis.^{2, 3}

Given the risks of heparin, the implications for practice for the review should say that heparin should not be used for pregnant women with acquired or inherited thrombophilias outside of a placebo or antiplatelet agent controlled RCT.

1. Abou-Nassar K, Kovacs MJ, Kahn SR, et al. The effect of dalteparin on coagulation activation during pregnancy in women with thrombophilia. A randomized trial. Thromb Haemost. 2007;98(1):163-171.

2. Thromboprophylaxis during pregnancy, labour and after vaginal delivery. (Guideline; no. 37). Royal College of Obstetricians and Gynaecologists (RCOG): London (UK). January 2004. Available at: http://www.rcog.org.uk/resources/Public/pdf/Thromboprophylaxis_no037.pdf.

3. Bates SM, Greer IA, Hirsh J, Ginsberg JS. Use of Antithrombotic Agents During Pregnancy: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. September 1, 2004;126(3_suppl):627S-644.