Adjustment of therapeutic LMWH to achieve specific target anti-FXa activity does not affect outcomes in pregnant patients with venous thromboembolism
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Venous thromboembolism (VTE) remains a leading cause of maternal morbidity and mortality in the developed world. Low molecular weight heparins (LMWH) are routinely used to provide therapeutic anticoagulation during pregnancy for women with VTE, with measurement of plasma anti-FXa activity used to guide dosing in certain patient groups. There is limited evidence to support the use of anti-FXa monitoring in pregnant patients. This study seeks to ascertain whether anti-FXa monitoring of pregnant patients with VTE influences patient outcomes. We performed a single-centre case series including two consecutive groups of pregnant patients treated with LMWH for VTE sustained in the index pregnancy with and without monitoring of anti-FXa levels. 35,394 patients delivered during the study period in a large urban stand-alone maternity hospital, with 26 cases of VTE eligible for inclusion. There was no significant difference between the two groups in any clinical outcome; including maternal blood loss at delivery, recurrent thromboembolic events or rates of planned delivery. These data provide clinical evidence to support current international guideline recommendations that measurement of plasma anti-FXa activity in the majority of patients receiving therapeutic-intensity antenatal LMWH is not warranted.
KeywordsFactor Xa Low molecular weight heparin Pregnancy Tinzaparin Venous thrombosis
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Conflict of interest
The authors report no conflict of interest.
- 1.Knight M, Kenyon S, Brocklehurst P, Neilson J, Shakespeare J, Kurinczuk JJ (2014) on behalf of MBRRACEUK. Saving lives, improving mothers’ care lessons learned to inform future maternity care from the UK and Ireland confidential enquiries into maternal deaths and morbidity. Oxford: National perinatal epidemiology unit, University of oxford 2009–2012Google Scholar
- 3.Bates SM, Greer IA, Middeldorp S, Veenstra DL, Prabulos AM (2012) Vandvik PO; American college of chest physicians. VTE, thrombophilia, antithrombotic therapy, and pregnancy: antithrombotic therapy and prevention of thrombosis, 9th ed: american college of chest physicians evidence-based clinical practice guidelines. Chest 141:e691S–e736SCrossRefPubMedPubMedCentralGoogle Scholar
- 13.Garcia DA, Baglin TP, Weitz JI, Samama MM (2012) American college of chest physicians parenteral anticoagulants: antithrombotic therapy and prevention of Thrombosis, 9th ed: american college of chest physicians evidence-based clinical practice guidelines. Chest 141:e24S–e43SCrossRefPubMedPubMedCentralGoogle Scholar
- 16.The acute management of thrombosis and embolism during pregnancy and the puerperium. Royal College of Obstetricians and Gynaecologists Green-top Guideline No. 37b (2007)Google Scholar