Anticoagulation in the pregnant woman

At Northside Hospital Heart Institute's Heart of the Matter conference earlier this year, I had the opportunity to present on the significance of anticoagulation in pregnant women. Physiological changes of pregnancy, including continuous changes in volume distribution, can affect the pharmacokinetics and ultimately the efficacy of medications, such as anticoagulants.

Not only is it important to understand pregnancy’s effect on medication metabolism, but also its effect on the coagulation cascade — for example, increased concentration of factors VII, VIII, X and vWF, as well as fibrinogen¹ — which can remain elevated for more than eight weeks postpartum and may warrant anticoagulation therapy. 

The choice of anticoagulation agent and dosing schedule depends on the indication, as well as the risk versus benefit of the medication to the mother and baby. Unfractionated heparin, low molecular weight heparin and warfarin are the most commonly used anticoagulants in pregnancy. 

The timing of anticoagulation discontinuation in preparation for delivery is vital, and the cessation risk, anesthesia options and mode of delivery should be considered.

Reference: 

1. Simcox, Louise E., et al. "Managing pulmonary embolism during pregnancy." Breathe (Sheff) 11, no. 4 (2015): 282-89.