Bayer Pharma AG

Essence of this Article

A risk of bleeding can be associated with any anticoagulation therapy; however, in pregnant patients, other safety concerns may also need to be considered. The use of unfractionated heparin (UFH) during pregnancy is associated with reduced bone density, vertebral fracture and a small risk of heparin-induced thrombocytopenia (HIT). Low molecular weight heparin (LMWH) use for the treatment or prevention of acute venous thromboembolism (VTE) during pregnancy is associated with adverse events including arterial thrombosis, osteoporosis, bleeding and allergic skin reactions. Adverse events such as HIT, bleeding and osteoporosis have been shown to occur at a lower frequency in patients receiving LMWHs compared with those receiving UFH. Vitamin K antagonists (VKAs) are not recommended during pregnancy.

Safety of anticoagulation during pregnancy

Anticoagulation therapy can be associated with a risk of bleeding. In pregnant patients, other safety concerns may also need to be considered.

In addition to risk of bleeding, the use of UFH during pregnancy may be associated with reduced bone density, vertebral fracture and a small risk of HIT.263

In a systematic review of the efficacy and safety of LMWH use for the treatment or prevention of acute VTE during pregnancy, adverse events included arterial thrombosis, osteoporosis, bleeding and allergic skin reactions; however, all adverse events occurred at a low frequency.273 In addition, adverse events such as HIT, bleeding and osteoporosis have been shown to occur at a lower frequency in patients receiving LMWH compared with those receiving UFH.267

VKAs, such as warfarin, have been associated with teratogenic effects, in addition to foetal wastage and bleeding, and are not recommended during pregnancy.267


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