Low-molecular-weight heparin for immediate management of thromboembolic disease in pregnancy

Abstract

women had epidural anaesthesia without complication. The fourth woman stayed in hospital and was delivered under spinal anaesthetic by caesarean section for placenta praevia. Intrapartum blood loss for each woman was within normal limits. Median peak (3 h) anti-Xa activity in the four women was 0·67 U/mL (range 0·46–1·00 on 18 observations). In one woman (weight 58 kg), a 24 h anti-Xa activity profile showed that a measurable protective anticoagulant effect (activity >0·2 U/mL) was maintained between drug administration (figure). Furthermore, in each woman, there was no cumulative anticoagulant effect. One woman, treated for 8 weeks, had monthly peak concentrations of anti-Xa of 1·00 U/mL, 1·00 U/mL, and 0·89 U/mL. The activated partial thromboplastin time for each woman remained within normal during enoxaparin treatment and no woman developed thrombocytopenia. Subcutaneous LMWH seems to have advantages over unfractionated heparin for venous thromboembolism in pregnancy. The simplified therapeutic regimen for LMWH enables patients to be treated as outpatients. LMWHs have a higher anti-factor Xa activity/anti-factor IIa activity ratio than unfractionated heparin and a more predictable dose response. LMWH may be a safe and effective treatment for venous thromboembolism in pregnancy with easy administration. Assessment of anti-Xa during treatment should, however, be carried out until greater experience is obtained.