From the Guidelines
For a 34-year-old patient with pulmonary embolism who is actively trying to become pregnant, low molecular weight heparin (LMWH) such as enoxaparin is the recommended anticoagulant of choice. The typical dosing for enoxaparin is 1 mg/kg subcutaneously twice daily or 1.5 mg/kg once daily, as recommended by the 2019 ESC guidelines for the diagnosis and management of acute pulmonary embolism 1. Treatment should continue for at least 3 months for the acute PE, and if pregnancy occurs during this time, LMWH should be continued throughout the pregnancy and for 6 weeks postpartum. LMWH is preferred because it does not cross the placenta and therefore doesn't pose risks of fetal bleeding or teratogenicity. Warfarin is contraindicated as it crosses the placenta and can cause fetal warfarin syndrome and bleeding complications. Direct oral anticoagulants (DOACs) like apixaban, rivaroxaban, and dabigatran are also not recommended as there is insufficient safety data for their use during pregnancy, as stated in the 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism 1. Regular monitoring of anti-Xa levels may be considered during pregnancy to ensure appropriate dosing, especially in women with extremes of body weight or renal dysfunction, as suggested by the guidelines on the diagnosis and management of acute pulmonary embolism: the task force for the diagnosis and management of acute pulmonary embolism of the European Society of Cardiology (ESC) 1. The patient should be advised that LMWH requires daily subcutaneous injections, but this approach provides the safest option for both maternal and fetal outcomes.
Some key points to consider in the management of this patient include:
- The importance of avoiding overdiagnosis of PE in pregnancy, as it can have significant implications for the patient, including the risk of bleeding at the time of delivery and the requirement for thromboprophylaxis during future pregnancies 1.
- The need for close collaboration between the obstetrician, anaesthesiologist, and attending physician in the management of labour and delivery, particularly in patients receiving therapeutic LMWH 1.
- The recommendation to discontinue LMWH at least 24 hours before planned delivery, and to resume treatment 12-24 hours after removal of the epidural catheter, as stated in the 2019 ESC guidelines 1.
- The importance of considering the risks and benefits of anticoagulant therapy during pregnancy, and of individualizing treatment based on the patient's specific clinical circumstances, as recommended by the American Society of Hematology 2018 guidelines for management of venous thromboembolism: venous thromboembolism in the context of pregnancy 1.
From the Research
Anticoagulation Options for Pulmonary Embolism in Pregnancy
The patient's condition of pulmonary embolism (PE) requires anticoagulation therapy, and since she is actively trying to become pregnant, the choice of anticoagulant is crucial. Considering the patient's age (34 years) and condition, the following options are available:
- Low molecular weight heparin (LMWH) is a preferred choice for anticoagulation in pregnancy due to its safety profile and efficacy in preventing venous thromboembolism (VTE) 2, 3, 4, 5.
- Unfractionated heparin (UFH) is also an option, but LMWH is generally considered safer and more convenient 2, 3.
- Coumarins, such as warfarin, are contraindicated in pregnancy due to the risk of embryopathy and fetal bleeding 3, 4.
Safety and Efficacy of Low Molecular Weight Heparin
Studies have shown that LMWH is a safe and effective anticoagulant in pregnancy, with a lower risk of osteoporosis and heparin-induced thrombocytopenia (HIT) compared to UFH 5.
- A systematic review of LMWH use in pregnancy found that the incidence of adverse fetal outcomes was comparable to that of the general population 5.
- Another study found that bleeding complications, including postpartum hemorrhage (PPH) and transfusion, were not increased in patients treated with LMWH during pregnancy compared to controls 6.
Recommendations
Based on the available evidence, LMWH is the recommended choice of anticoagulation for the patient, given its safety profile and efficacy in preventing VTE in pregnancy 2, 3, 4, 5. The patient should be closely monitored for any potential complications, and the treatment plan should be adjusted as needed to ensure the best possible outcome for both the patient and the fetus.