A randomized controlled trial of differing doses of postcesarean enoxaparin thromboprophylaxis in obese women

To compare two enoxaparin dosing strategies at achieving prophylactic anti-Xa levels in women with a body mass index (BMI) ⩾35 (kg m(-2)) postcesarean delivery.

Women with BMI ⩾35 were randomized to receive prophylactic enoxaparin at a fixed dose of 40 mg daily or weight-based dosing of 0.5 mg kg(-1) twice daily. The primary outcome was the proportion of subjects with peak anti-Xa levels in the prophylactic range of 0.2 to 0.6 IU ml(-1).

From August 2013 through February 2014, 84 demographically similar women completed the protocol. In the weight-based group, 88% (37/42) of the women reached prophylactic anti-Xa levels versus 14% (6/42) in the fixed dose group (odds ratio 44.4, 95% confidence interval 12.44, 158.48, P<0.001). No anti-Xa level exceeded 0.48 IU ml(-1). There were no venous thromboembolic or bleeding events requiring reoperation or transfusion in either group.

Compared with fixed dosing daily, weight-based dosing twice daily more effectively achieved prophylactic anti-Xa levels without reaching the therapeutic range.