From the Guidelines
The recommended DVT prophylaxis for pregnant women at increased risk includes low molecular weight heparin (LMWH) such as enoxaparin 40mg subcutaneously once daily or dalteparin 5,000 units subcutaneously once daily. This is based on the most recent and highest quality study available, which suggests that LMWH is the preferred choice for DVT prophylaxis in pregnant women due to its lower risk of heparin-induced thrombocytopenia and osteoporosis with long-term use, as well as its safety profile for the fetus 1.
Key Considerations
- Prophylaxis should begin early in pregnancy and continue for at least 6 weeks postpartum.
- For women with higher risk factors (previous DVT, thrombophilia, multiple risk factors), higher doses may be needed, such as enoxaparin 40mg twice daily.
- Mechanical methods like graduated compression stockings (20-30 mmHg) can be used as adjunctive therapy or when anticoagulation is contraindicated.
- Early mobilization after delivery is also important.
- Risk assessment should be performed early in pregnancy and repeated if hospitalization occurs or complications develop.
Specific Recommendations
- For pregnant women who are heterozygous for factor V Leiden or prothrombin gene mutation, antepartum clinical surveillance is suggested, regardless of family history of VTE 1.
- For pregnant women who are protein C or protein S deficient, antepartum clinical surveillance is suggested, regardless of family history of VTE 1.
- For pregnant women who are compound heterozygotes or homozygous for factor V Leiden or prothrombin gene mutation, antepartum prophylactic- or intermediate-dose LMWH is suggested, especially in the presence of a positive family history of VTE 1.
Rationale
The preference for LMWH over unfractionated heparin and warfarin is due to its safety profile and efficacy in preventing DVT in pregnant women, as supported by the American Society of Hematology 2018 guidelines for management of venous thromboembolism in pregnancy 1.
From the Research
DVT Prophylaxis in Pregnancy
The recommended Deep Vein Thrombosis (DVT) prophylaxis for pregnant women includes the use of low-molecular-weight heparin (LMWH) products, such as enoxaparin, tinzaparin, and nadroparin 2, 3, 4, 5.
- Enoxaparin: Can be used safely in DVT therapy during pregnancy, with a single daily dose of 1.5 mg/kg being as effective as twice-daily administration 2.
- Tinzaparin: Has been shown to be safe and effective in high-risk pregnancies, with a dose of 175 IU/kg once daily 4.
- Nadroparin: Can be used to prevent thromboembolic complications in pregnant women with heart valve prostheses, and to prevent fetal loss in women with antiphospholipid syndrome 5.
Administration and Dosage
The administration and dosage of LMWH products may vary depending on the individual patient's risk factors and medical history.
- Prophylactic dose: Nadroparin can be administered at a prophylactic dose of 0.3 ml (2850 IU AXa, 95 IU/kg) s.c. once daily, with a therapeutic dose of 0.1 ml/10 kg (95 IU/kg) s.c. twice daily 5.
- Monitoring: Peak anti-Xa levels may need to be monitored and adjusted accordingly, with dose modification occurring in 45% of cases examined 4.
Safety and Efficacy
LMWH products have been shown to be safe and effective in preventing DVT in pregnant women, with a low incidence of maternal and fetal complications 2, 3, 4, 5.