Cardiovascular Management in Pregnancy: Antithrombotic Agents and Antiplatelet Agents.

Abstract

Thrombotic complications of pregnancy are a major cause of morbidity and mortality to the mother and fetus. Pulmonary embolism is a leading cause of maternal death and accounts for 10.3% of all maternal deaths in the United States.1,2 Overall, pregnancy increases the risk of venous thromboembolism (VTE) 5-fold, with an additional increase in risk in the postpartum period.3,4 Pregnancy is associated with a hypercoaguable state attributable to relative increases in fibrinogen, plasminogen activator inhibitors, clotting factors VII, VIII, and X, von Willebrand Factor, and platelet adhesion molecules, and relative decreases in protein S activity, as well.5,6 Pregnancy is also a time of dramatic hemodynamic change including a reduction in lower extremity venous flow velocity by up to 50% at the end of the second trimester, which persists until 6 weeks postpartum.7 Recommendations for thrombosis prevention and anticoagulation in pregnant women are derived largely from algorithms from the nonpregnant population. We review the use of both older and new anticoagulants and antiplatelet medications during pregnancy and highlight their clinical utility in conditions including VTE, thrombophilias, mechanical heart valves, antiphospholipid syndrome (APLS), preeclampsia, intrauterine growth restriction (IUGR), and placental abruption. ### Vitamin K Antagonists #### Warfarin Warfarin is a vitamin K antagonist that easily crosses the placenta.8 Exposure in the first trimester is associated with warfarin embryopathy characterized by nasal bone hypoplasia and stippled epiphyses.9 Case series of pregnant women taking warfarin in the setting of mechanical heart valves found warfarin embryopathy rates of 5.6% and 6.4%, respectively.10,11 Warfarin use in the second and third trimester is associated with possible neurological sequelae including seizures, developmental delay, and hypotonia in the developing fetus attributable to intracranial microhemorrhages.12 Increased fetal risk for hemorrhage has been attributed to the greater affinity of albumin for bilirubin …