It’s early medical school teaching that pregnancy puts a patient at increased risk for thrombotic diseases like DVT and PE, but what can you do when you actually find one? Classic teaching and a quick poll of our residency (n=4) has everyone saying “Coumadin-no, heparin-yes.” While accurate and relatively well studied, it leaves out a third category of new(ish) medications: the DOAC/NOACs such as the thrombin inhibitor dabigatran and the factor Xa inhibitors like apixaban. These have the upside of being simple to start in the ED without any real teaching or an admission, but where do they fall in pregnant patients?
The current guidelines have them in the same category as coumadin and are not recommended (unfortunately). This comes from data from animal models and studies which showed some increased risk of fetal complications and maternal bleeding. There have been no significant human trials or data to suggest safety one way or the other, though. There was an observational study evaluating DOAC exposed pregnancies (usually women already on a DOAC who became pregnant) which showed 67 live births (48.9 %); 31 miscarriages (22.6 %); 39 elective pregnancy terminations (28.5 %). Of the cases with known outcomes, only 5% showed any embryo abnormalities, which the researchers reported as similar to the general population. Due to its small study size and lack of follow up for 40% of the total cases, however, no conclusions could be drawn to support DOAC use.
Bottom Line: Current guidelines recommend low molecular weight heparin as first line for AC in pregnancy. Coumadin is still a no. DOACs are also a no, though that has room to change if more data becomes available. (Also DOACs are a no in breast feeding.)
- Bates SM, Greer IA, Middeldorp S, et al. VTE, thrombophilia, antithrombotic therapy, and pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141:e691S.
- Cohen H, Arachchillage DR, Middeldorp S, et al. Management of direct oral anticoagulants in women of childbearing potential: guidance from the SSC of the ISTH. J Thromb Haemost 2016; 14:1673.
- Beyer-Westendorf J, Michalski F, Tittl L, et al. Pregnancy outcome in patients exposed to direct oral anticoagulants – and the challenge of event reporting. Thromb Haemost 2016; 116:651.