[Treatment with danaparoid during pregnancy for a woman with a cutenous allergy to low-molecular-weight heparin]

An analysis of clinical outcomes of 91 pregnancies in 83 women treated with danaparoid (Orgaran)

Danaparoid case reports of 91 pregnancies in 83 patients with a history of thrombophilia and/or intra-uterine growth retardation have been analysed. All had intolerance to the heparins including HIT and acute or past thromboses or a history of repeated pregnancy loss (RPL). Danaparoid was started in the first, second and third trimesters in 60.2%, 19.3% and 20.5% pregnancies respectively at a dosing intensity of 1000 to 7500 U/day. Subcutaneous and/or intravenous administration was continued for a median 105 days (range 1-252) during pregnancy and 7 days (range 2 to 56) post-partum. The live birth rate was 90.4% (75/81) and danaparoid was restarted after 37 deliveries. Maternal adverse events in 46.2% of the pregnancies included 2 post cesarean deaths (a failed post-operative resuscitation and a major bleed in a patient refusing transfusion), 3 non-fatal major bleeds (associated with cesarean section and faulty placental implantation), 3 thrombo-embolic events unresponsive to danaparoid dose increase and 10 recurrent rashes. Seven early miscarriages, 1 therapeutic termination and 1 neonatal death occurred. In 13 reports a maternal, but no fetal, adverse event was attributed to danaparoid. Anti-Xa activity levels in maternal plasma were between 0.1 and 1.2 U/mL, absent from 6 fetal cord blood samples and 0 - 0.07 U/mL in the 5 maternal breast milk samples tested.

CONCLUSION

The successful birth rate and adverse event profile indicates that danaparoid can be an effective and safe alternative anti-thrombotic in pregnancies complicated by HIT or intolerance or resistance to (LMW)heparins.

Prevention and management of venous thromboembolism in pregnancy

Normal pregnancy is accompanied by an increase in clotting factors. The resulting hypercoagulable state has likely evolved to protect women from hemorrhage at the time of miscarriage and childbirth. During pregnancy, women are 4 times more likely to suffer from venous thromboembolism (VTE) compared with when they are not pregnant. Relative to pregnancy, the risk postpartum is even higher. The incidence of VTE is approximately 2 per 1,000 births, and VTE accounts for 1 death per 100,000 births, or approximately 10% of all maternal deaths. The most important risk factors during pregnancy are thrombophilia and a history of thrombosis. A history of thrombosis increases the risk for VTE to 2% to 12%. Thrombophilia increases not only the risk for maternal thrombosis but also the risk of poor pregnancy outcome. Despite the increased risk for thrombosis during pregnancy and the postpartum period, most women do not require anticoagulation. Those who do require anticoagulation include women with current VTE, women on lifelong anticoagulation, and many women with thrombophilia or a history of thrombosis. Recommended options for anticoagulation in pregnancy are limited to heparins, which do not cross the placenta. Low-molecular-weight heparin (LMWH) is preferred over unfractionated heparin because LMWH has a longer half-life and is presumed to have fewer side effects. The longer half-life is a disadvantage around the time of delivery, when unfractionated heparin, with its shorter half-life, is easier to manage. For women who develop or are at high risk for heparin-induced thrombocytopenia or severe cutaneous reactions, fondaparinux is probably the agent of choice. Women who do not require lifelong anticoagulation, but require anticoagulation during pregnancy, will still require anticoagulation for the first 6 weeks postpartum.

Anticoagulants in Pregnancy

Pregnancy is a hypercoagulable state that increases the risk of thromboembolic events. These risks may be further increased in the presence of an acquired or inherited thrombophilia. Thrombophilias have been associated with both maternal and fetal complications. The use of anticoagulants during pregnancy may reduce the risk of maternal thromboses as well as the risk of adverse pregnancy outcomes. The choice of an anticoagulant requires consideration of maternal risks, potential for teratogenicity, the underlying condition necessitating the treatment, and cost. This review examines the options for anticoagulation, the clinical situations that may warrant such treatment, and factors to be considered at delivery and during the postpartum period.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe the roles of acquired and inherited thrombophilia in furthering the hypercoagulable state of pregnancy, identify the potential consequences of using anticoagulants during pregnancy, and summarize the treatment options when anticoagulation is required during pregnancy.