Prophylactic Low-Molecular-Weight Heparin Versus Unfractionated Heparin at the Time of Delivery [32L

Abstract

INTRODUCTION: To compare the impact of two common dosing practices of antepartum prophylactic anticoagulation on peripartum management. METHODS: IRB approval was obtained for this retrospective cohort study of women receiving prophylactic anticoagulation from 2014 to 2019. Two strategies were reviewed: continuation of low-molecular weight heparin (LMWH) until delivery vs transitioning from LMWH to unfractionated heparin (UFH) at 36 weeks. Strategies were compared for impact on obstetric outcomes and anesthesia for delivery. RESULTS: Prophylactic anticoagulation was identified in 66 women; 48 (73%) remained on LMWH until delivery and 18 (27%) were transitioned to UFH. LMWH dosing ranged from 30 to 80 mg daily (88% at 40 mg). UFH was dosed at either 5,000 U twice daily (56%) or 10,000 U twice daily (44%). Comparing outcomes, both groups had similar rates of delivery during a scheduled admission (65% vs 50%, P=.40) and receiving neuraxial analgesia (79% vs 89% P=.50). Four women receiving LMWH (8%) did not receive neuraxial analgesia due to timing of their last dose (range 5-12 hours); one of these patients received general anesthesia for a cesarean, and the other three received intravenous analgesia for labor. In the LMWH group, seven women (15%) had an estimated blood loss (EBL) >1000 cc compared to none in the UFH group (P=.18) A multiple regression model showed no effect of anticoagulation strategies on EBL when adjusted for route of delivery, maternal weight and birthweight (P=.18). CONCLUSION: Among women receiving prophylactic LMWH, transition to UFH before delivery did not significantly impact receipt of neuraxial analgesia or lower rates of postpartum hemorrhage.