Thromboprophylaxis with low molecular mass heparin, `Fragmin' (dalteparin), during pregnancy -- a longitudinal safety study

TITLE: Thromboprophylaxis with low molecular mass heparin, `Fragmin' (dalteparin), during pregnancy -- a longitudinal safety study

JOURNAL: Blood Coagulation and Fibrinolysis
VOLUME: 09
ISSUE: 01
PAGES: 0001-0009

AUTHOR: M. Blomback, K. Bremme, M. Hellgren, A. Siegbahn, H. Lindberg

ADDRESS: Department of Laboratory Medicine/Coagulation Research , Stockholm , Sweden. Department of Woman and Child Health, the Karolinska Institute/Karolinska Hospital , Stockholm , Sweden. Department of Obstetrics and Gynaecology, Sahlgrenska University Hospital , Molndal , Sweden. Department of Clinical Chemistry, Uppsala Academic Hospital , Uppsala , Sweden. Pharmacia & Upjohn , Stockholm , Sweden

ABSTRACT: Twenty-five women with previous verified thromboembolic complications were treated with dalteparin (Fragmin®) during pregnancy and puerperium. Women with known hereditary thrombophilia (antithrombin, protein C and protein S deficiencies) or with phospholipid antibodies were excluded. The dose at entry was calculated according to body weight and thereafter monitored by anti-FXa activity aiming at 0.20--0.40 IU/ml plasma 3 h post injection. Dalteparin or dextran was used during delivery. Twenty-two women completed the study and 14 of these could be given the same dose throughout pregnancy. There was an increased dose response postpartum. There were no thromboembolic recurrences or severe bleeding complications. The level of antithrombin activity remained normal. Our thrombosis-prone pregnant women had initially increased levels of thrombin markers but no further increase was observed during the dalteparin thromboprophylaxis. Retrospectively,three heterozygous and three homozygous individuals for the FV Leiden mutation leading to activated protein C resistance were identified. In conclusion, dalteparin could safely be used as thromboprophylaxis during pregnancy in these thrombosis-prone women. Women weighing 50--79 kg at entry could be treated with 5000 IU of dalteparin once daily during pregnancy, without monitoring. Postpartum, many of the women were given a reduced dose. Blood Coag Fibrinol 9:1--9 © 1998Rapid Science Ltd.

KEYWORDS: thromboprophylaxis LMM heparin anti-FXa pregnancy thrombin markers