title: Adjustment of therapeutic LMWH to achieve specific target anti-FXa activity does not affect outcomes in pregnant patients with venous thromboembolism.
abstract: 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.
authors: Department of Obstetrics, Rotunda Hospital, Parnell Street, Dublin 1, Ireland. bmcdonnell@rcsi.ie.
authors: Brendan P
authors: BP
authors: McDonnell
authors: Department of Obstetrics, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.
authors: Kate
authors: K
authors: Glennon
authors: Department of Obstetrics, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.
authors: Aoife
authors: A
authors: McTiernan
authors: Department of Obstetrics, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.
authors: Hugh D
authors: HD
authors: O'Connor
authors: Department of Obstetrics, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.
authors: Colin
authors: C
authors: Kirkham
authors: Department of Hematology, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.
authors: Barry
authors: B
authors: Kevane
authors: Department of Obstetrics, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.
authors: Jennifer C
authors: JC
authors: Donnelly
authors: Department of Hematology, Rotunda Hospital, Parnell Street, Dublin 1, Ireland.|Department of Hematology, Mater Misericordiae University Hospital, Dublin 7, Ireland.|School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland.
authors: Fionnuala
authors: F
authors: Ni Áinle
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring; D065427:Factor Xa Inhibitors / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000188:drug therapy*; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000188:drug therapy*
chemical_list: D000925:Anticoagulants; D065427:Factor Xa Inhibitors; D006495:Heparin, Low-Molecular-Weight
keywords: Factor Xa; Low molecular weight heparin; Pregnancy; Tinzaparin; Venous thrombosis