Thromboprophylaxis in Pregnancy: What Dose of Low-Molecular-Weight Heparin Is Best?

For women in early pregnancy with prior venous thromboembolism (VTE), we must balance our thromboprophylaxis decisions between risk for recurrent VTE and risk for major bleeding. Data to inform such decisions have largely been extrapolated from studies of nonpregnant women, with limited understanding of how physiological changes of pregnancy affect efficacy.

In this multicenter international trial, investigators randomized 1110 pregnant women with prior VTE (defined as “unprovoked or provoked by hormonal or minor risk factors”) to either low-dose or intermediate-dose low-molecular-weight heparin (LMWH). All dosing was once daily and continued until 6 weeks postpartum (paused at time of delivery). Choice of LMWH varied by country, and dosing …