From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
For a 10-week pregnant patient with a recent stroke and patent foramen ovale (PFO), therapeutic dosing of Lovenox (enoxaparin) is recommended rather than prophylactic dosing, with a regimen of 1 mg/kg subcutaneously twice daily, as supported by the most recent study 1. The therapeutic approach is preferred because the patient has experienced a thromboembolic event (stroke) with an identified risk factor (PFO), which creates a higher risk for recurrent events. During pregnancy, hypercoagulability increases, further justifying full anticoagulation. The PFO provides a potential route for paradoxical embolism, where clots can bypass pulmonary filtration and enter arterial circulation. Some key points to consider in the management of this patient include:
- The use of enoxaparin in pregnancy is well-established, with a study from 2007 2 demonstrating its safety and efficacy in preventing venous thromboembolism and pregnancy complications.
- A study from 2016 3 highlights the importance of considering PFO-related stroke in pregnant women, particularly in the first and second trimesters.
- The effectiveness and safety of thromboprophylaxis with enoxaparin for prevention of pregnancy-associated venous thromboembolism has been demonstrated in a large observational cohort study 1.
- Factor Xa monitoring is indicated in this case due to pregnancy, which alters drug metabolism and distribution, with target anti-Xa levels of 0.6-1.0 IU/mL for therapeutic anticoagulation, measured 4 hours after injection, as suggested by the example answer. Therapeutic anticoagulation should continue throughout pregnancy and for at least 6 weeks postpartum, with consideration for transition to warfarin after delivery if long-term anticoagulation is needed.