From the Guidelines
Women with Factor V Leiden who have experienced recurrent miscarriages should be considered for anticoagulation therapy with low molecular weight heparin (LMWH) and low-dose aspirin during pregnancy to reduce the risk of further miscarriages. Factor V Leiden mutation has been associated with an increased risk of recurrent fetal loss, possibly due to placental thrombosis 1. The use of LMWH, such as enoxaparin (40mg daily) or dalteparin (5000 units daily), combined with low-dose aspirin (81mg daily), may be beneficial in preventing miscarriages in women with Factor V Leiden who have a history of multiple pregnancy losses.
Some key points to consider in the management of women with Factor V Leiden and recurrent miscarriages include:
- The treatment typically begins as soon as pregnancy is confirmed and continues until 6 weeks postpartum 1.
- The rationale behind this treatment is that Factor V Leiden causes resistance to activated protein C, leading to increased thrombin generation and potential placental thrombosis 1.
- Anticoagulation therapy helps prevent these small clots from forming in the placental vessels, which can compromise blood flow to the developing fetus, resulting in miscarriage.
- Treatment decisions should be individualized based on the woman's complete thrombophilia profile, personal and family history of thrombosis, and previous pregnancy outcomes 1.
- Women with Factor V Leiden should also be monitored more closely during pregnancy with additional ultrasounds to assess fetal growth and placental function.
It is essential to note that the decision to use anticoagulation therapy in women with Factor V Leiden and recurrent miscarriages should be made on a case-by-case basis, taking into account the potential benefits and risks of treatment, as well as the woman's individual circumstances and medical history 1.
From the Research
Factor V Leiden and Miscarriage
- Factor V Leiden is a common thrombophilic mutation that has been associated with an increased risk of miscarriage 2, 3, 4, 5, 6
- Studies have shown that women with Factor V Leiden have a higher risk of recurrent miscarriage compared to those without the mutation 3, 5, 6
- The use of low molecular weight heparin (LMWH) has been shown to reduce the risk of miscarriage in women with Factor V Leiden 2, 4
- Aspirin has also been used in combination with LMWH to prevent miscarriage in women with Factor V Leiden, but its effectiveness is still debated 2
- The risk of miscarriage is higher in women with a history of recurrent early miscarriage who carry the Factor V Leiden allele compared to those with a normal Factor V genotype 3
- Factor V Leiden has also been associated with other pregnancy complications, including preeclampsia, placental abruption, and intrauterine fetal growth restriction 2, 4
Prevention of Miscarriage
- LMWH prophylaxis has been shown to reduce the risk of obstetric complications, including miscarriage, in carriers of Factor V Leiden 4
- The use of LMWH plus aspirin has been shown to have comparable live birth rates to LMWH alone in women with Factor V Leiden and recurrent pregnancy loss 2
- Testing for Factor V Leiden is recommended in women who have experienced recurrent miscarriages, as it may help identify those at increased risk of pregnancy complications 5
- Women with Factor V Leiden may benefit from targeted thromboprophylaxis during future pregnancies to reduce the risk of miscarriage and other pregnancy complications 3, 4