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Patient Evidence Summary
Doctor, I have a blood clotting disorder that runs in my family. Do I need an anticoagulant during pregnancy?
Small doses of low molecular weight heparin (Fragmin©) given during pregnancy do not reduce the risk of DVT, PE, pregnancy loss or placenta complications in pregnant women with known blood clotting disorders (thrombophilia). However, it is important to note that this study did not include women with recurrent pregnancy losses due to antiphospholipid antibody syndrome or women with a prior unexplained DVT or PE.
Study highlights
Women with thrombophila who injected small doses of low molecular weight heparin (Fragmin© 5000 IU) during pregnancy did not have a lower risk of DVT, PE or placenta complications, and they did have a higher risk of minor bleeding.
Understanding the problem
People with thrombophilia have an increased risk of developing DVT or PE. Also, some pregnancy complications (i.e., pre-eclampsia, small-for-gestational-age infant, placental abruption or pregnancy loss) are more common in women with thrombophilia. These complications are thought to be caused by blood clots in very small blood vessels within the placenta.
The link between thrombophilia, DVT, PE and placenta complications has led to the question of whether women with thrombophliia would have fewer complications during pregnancy if they took anticoagulants to prevent their blood from clotting so easily.
This study was performed to determine if small doses of low molecular weight heparin injected during pregnancy reduces the risk of recurrent DVT, PE and placenta complications in pregnant women with known thrombophilia.
Who? The study included 292 pregnant women (average age 32 years) who had thrombophilia confirmed by a blood test and were at high-risk of DVT, PE or placenta complications because they had (1) a past history of DVT or PE OR (2) a past history of pre-eclampsia, unexplained small-for-gestational-age infant, placental abruption or pregnancy loss OR (3) a first-degree relative with a history of DVT or PE.
Thrombophilias were identified using blood tests. They included Factor V Leiden mutation, Prothrombin gene mutation, Protein C deficiency, Protein S deficiency, Antithrombin deficiency, or Antiphospholipid antibody. Women with a history of recurrent pregnancy losses in the setting of Antiphospholipid antibody syndrome or with a prior unprovoked DVT or PE were excluded.
What? The study compared the risk of DVT, PE and placenta complications in pregnant women who injected small doses of low molecular weight heparin (Fragmin©) during pregnancy with those who did not.
Fragmin© | vs | No Treatment |
|---|---|---|
Fragmin© 5000 IU once daily by subcutaneous injection until 20 weeks gestational age followed by 5000 IU twice daily from 20 weeks until at least 37 weeks gestational age. Injections were started at an average of 12 weeks gestational age. | No treatment |
Fragmin© 5000 IU injections versus no treatment in pregnant women with thrombophilia
Outcomes at 6 weeks after delivery | Rate of events with Fragmin© | Rate of events with no treatment | Results |
|---|---|---|---|
Symptomatic DVT or PE OR severe/early pre-eclampsia OR small-for-gestational age-infant OR pregnancy loss | 17 out of 100 women | 19 out of 100 women | No difference* |
| Major bleeding | 2 out of 100 women | 1 out of 100 women | No difference* |
| Minor bleeding | 20 out of 100 women | 9 out of 100 women | About 11 more women out of 100 had minor bleeding while injecting Fragmin© |
*Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the difference could simply be due to chance rather than due to the different treatments.
This Evidence Summary is based on the following article:
Rodger MA, Hague WM, Kingdom J, et al. Antepartum dalteparin versus no antepartum dalteparin for the prevention of pregnancy complications in pregnant women with thrombophilia (TIPPS): a multinational open-label randomised trial. Lancet. 2014 Nov 8;384(9955):1673-83. doi: 10.1016/S0140-6736(14)60793-5. Epub 2014 Jul 24. PubMed
Erica Kelly, MD, FRCPC
Erica Kelly is a fifth-year Hematology resident at Dalhousie University. She completed her MD and Internal Medicine training at Memorial University of Newfoundland and has a diploma in Clinical Epidemiology.
Lori-Ann Linkins, MD, MSc (Clin Epi), FRCPC
Dr. Linkins is an Associate Professor of Medicine (thrombosis) at McMaster University in Hamilton, Canada. She holds a Masters Degree in Health Research Methodology and is a Deputy Editor with the Health Information Research Unit, McMaster. Her research interests include heparin-induced thrombocytopenia and cancer-associated thrombosis. She was editor of the ACCP Guidelines, 9th Edition HIT chapter and is currently a member of the ASH VTE Guidelines HIT Panel.
Published: Tuesday, March 17, 2020
Last Updated: Thursday, July 30, 2020
Please note that the information contained herein is not to be interpreted as an alternative to medical advice from a professional healthcare provider. If you have any questions about any medical matter, you should consult your professional healthcare providers, and should never delay seeking medical advice, disregard medical advice or discontinue medication based on information provided here.
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, McMaster University