Antenatal use of enoxaparin for prevention and treatment of thromboembolism in pregnancy

Objective To assess the safety and efficacy of enoxaparin use for thromboprophylaxis or treatment of venous thromboembolism during pregnancy. Design Retrospective review of casenotes of women who received enoxaparin during pregnancy. Setting Obstetric Medicine Unit at Glasgow Royal Maternity Hospital. Sample Data were obtained on 57 pregnancies in 50 women over six years. Methods Information was obtained from case records in relation to outcome measures, the presence of underlying thrombophilia and indication for anticoagulation. Main outcome measures Incidences of venous thromboembolism, haemorrhage, thrombocytopenia, peak plasma anti-factor Xa levels and symptomatic osteoporosis. Results There were no thromboembolic events in the thromboprophylaxis group. There were no incidences of heparin-induced thrombocytopenia. Twenty-two women had spinal or epidural anaesthesia and no complications were encountered. There was one instance of antepartum haemorrhage following attempted amniotomy in a woman with previously unknown vasa praevia. Two women sustained postpartum haemorrhage, both secondary to vaginal lacerations, resulting in blood loss > 1000 mL. Blood loss following caesarean section was not excessive. No instances of vertebral or hip fracture were encountered. The median peak plasma anti-factor Xa level on a dose of 40 mg once daily was 0.235 U/mL; peak plasma anti-factor Xa levels were not affected by gestational age. Conclusions The use of enoxaparin in pregnancy is associated with a low incidence of complications and a dose of 40 mg once daily throughout pregnancy provides satisfactory anti-factor Xa levels and appears effective in preventing venous thromboembolism.