Prophylaxis with low‐dose low‐molecular‐weight heparin during pregnancy and postpartum: is it effective?

• Published in: Journal of thrombosis and haemostasis 2011-03, Vol.9 (3), p.473-480
• Main Authors: ROETERS VAN LENNEP, J. E., MEIJER, E., KLUMPER, F. J. C. M., MIDDELDORP, J. M., BLOEMENKAMP, K. W. M., MIDDELDORP, S.
• Format: Article
• Language: English
• Subjects: Adult; Anticoagulants - adverse effects; Anticoagulants - pharmacology; Cohort Studies; Female; Heparin, Low-Molecular-Weight - adverse effects; Heparin, Low-Molecular-Weight - pharmacology; Humans; low‐molecular‐weight heparin; postpartum hemorrhage; Postpartum Hemorrhage - etiology; Pregnancy; Pregnancy Complications, Cardiovascular - prevention & control; Puerperal Disorders - prevention & control; pulmonary embolism; Retrospective Studies; Risk Factors; thromboembolism; Venous Thromboembolism - complications; Venous Thromboembolism - prevention & control; venous thrombosis
• ISSN: 1538-7933; 1538-7836; 1538-7836
• DOI: 10.1111/j.1538-7836.2011.04186.x

Background: The optimal approach for venous thrombosis (VTE) prophylaxis during pregnancy and postpartum in women with an increased risk of VTE is not established. Objectives: To evaluate the effectiveness, represented as the incidence of pregnancy‐related VTE, and safety, represented as incidence of postpartum hemorrhage (PPH), of a protocol recommending prophylaxis with low‐dose low‐molecular‐weight heparin (LMWH) in women at intermediate to high risk of VTE. Patients/methods: In this retrospective cohort study, we analyzed 34 women (44 pregnancies) with intermediate risk of VTE who received low‐dose LMWH for 6 weeks postpartum and 57 women (82 pregnancies) with high risk of VTE who received low‐dose LMWH during pregnancy and for 6 weeks postpartum. Pregnancy‐related VTE was defined as VTE during pregnancy or ≤ 3 months postpartum. PPH was defined as blood loss > 500 mL and severe PPH as blood loss > 1000 mL. Results: The incidence of pregnancy‐related VTE was 5.5% (95% CI, 2.4–12.3) despite prophylaxis with low‐dose LMWH. All events occurred in women at high risk, with a postpartum incidence of 7.0% (95% CI, 2.9–16.7) and antepartum incidence of 1.8% (95% CI, 0.4–9.2). The risk of PPH was 21.6% (95% CI, 14.3–31.3) and severe PPH 9.1% (95% CI, 4.7–16.9), which was not different in women who started LMWH postpartum and those who used LMWH during pregnancy. Conclusions: Although prophylaxis with low‐dose LMWH during pregnancy and postpartum proved to be safe, the risk of pregnancy‐related VTE is considerable in women with a high risk of VTE. VTE prophylaxis with low‐dose LMWH may not be sufficiently effective in these women.