From the Guidelines
Lovenox (enoxaparin) can be used during pregnancy, but with caution and careful monitoring.
Important Considerations
- Lovenox is a low-molecular-weight heparin (LMWH) that does not cross the placenta and is likely safe for the fetus 1.
- However, the use of LMWH during pregnancy remains controversial due to reports of treatment failures and safety concerns 1.
- In a clinical study, 2 of 8 women with prosthetic heart valves developed prosthetic valve thromboses while taking subcutaneous enoxaparin, leading to maternal and fetal death 1.
Monitoring and Dosing
- Plasma anti-Xa levels should be measured 4 to 6 hours after the morning dose and the dose of LMWH adjusted to achieve an anti-Xa level of approximately 0.7 to 1.2 units per ml 1.
- The dose of LMWH should be weight-adjusted, and adaptation according to anti-Xa monitoring may be considered in women at extremes of body weight or with renal disease 1.
Alternatives and Risks
- Unfractionated heparin (UFH) is an alternative to LMWH, but it has a higher risk of heparin-induced thrombocytopenia, osteoporosis, and bleeding complications 1.
- Warfarin crosses the placenta and is associated with a well-defined embryopathy during the first trimester, as well as fetal and neonatal hemorrhage in the third trimester 1.
From the Research
Use of Lovenox (Enoxaparin) During Pregnancy
- Enoxaparin is a low molecular weight heparin that can be used during pregnancy for the treatment and prevention of thromboembolism 2, 3, 4, 5, 6.
- International guidelines support the use of low molecular weight heparins, such as enoxaparin, for the treatment of thromboembolism and thromboprophylaxis during pregnancy 2.
- Studies have shown that enoxaparin is safe and effective for preventing thromboembolism and adverse obstetrical complications in pregnant women, including those with multiple gestations 3, 5, 6.
- The use of enoxaparin during pregnancy has been associated with a low incidence of complications, including bleeding events, thrombocytopenia, and osteoporotic fractures 3, 4, 5, 6.
- Enoxaparin does not cross the placenta and is safe for the fetus, with no reported cases of teratogenicity or congenital malformations 4.
Indications for Enoxaparin Use During Pregnancy
- Prophylaxis of venous thromboembolism 2, 3, 4, 5, 6.
- Prevention of pregnancy loss in thrombophilic women 2, 3, 4.
- Treatment of venous thromboembolism 5, 6.
- Prophylaxis of arterial thrombosis in pregnant women with mechanical heart valves 4.
- Prevention of late gestational complications, such as pre-eclampsia and intrauterine growth restriction 4.
Dosage and Administration
- The recommended dose of enoxaparin during pregnancy is 40 mg once daily, although some studies have used doses of 1 mg/kg twice daily or 1.5 mg/kg once daily 3, 5, 6.
- Enoxaparin should be discontinued 12-24 hours before delivery and restarted within 8-12 hours after delivery 6.
- Warfarin can be given as adjuvant therapy along with enoxaparin in the post-partum period 6.