OBJECTIVE: The purpose of this study was to determine whether standard therapeutic doses of dalteparin maintain peak therapeutic levels of anticoagulation during pregnancy. STUDY DESIGN: This was a prospective trial in which 13 pregnancies that required therapeutic anticoagulation were treated with dalteparin 100 U/kg every 12 hours; peak and trough (predose) low molecular weight heparin (anti-Xa activity) levels were monitored every 2 weeks. Dosage adjustments were made to maintain peak anti-Xa activity between 0.5 and 1.0 IU/ml. Bone density and bone turnover markers were measured. RESULTS: A total of 250 peak and trough low-molecular-weight heparin (LMWH) levels were obtained. Eighty-five percent of pregnancies (11/13) required an upward dosage adjustment. Trough levels were in the therapeutic range only 9% of the time, despite the maintenance of therapeutic peak levels. Bone resorption markers and density were unchanged in singleton pregnancies. CONCLUSION: Dalteparin dosing, based on weight alone, every 12 hours is inadequate to maintain most pregnant women in the therapeutic range throughout pregnancy as measured by anti-Xa activity. Trough levels are rarely in the therapeutic range, despite maintenance of therapeutic peak levels. These notable changes in low molecular weight heparin peak may explain reported failures in pregnancy.
OBJECTIVE: The purpose of this study was to determine whether standard therapeutic doses of dalteparin maintain peak therapeutic levels of anticoagulation during pregnancy. STUDY DESIGN: This was a prospective trial in which 13 pregnancies that required therapeutic anticoagulation were treated with dalteparin 100 U/kg every 12 hours; peak and trough (predose) low molecular weight heparin (anti-Xa activity) levels were monitored every 2 weeks. Dosage adjustments were made to maintain peak anti-Xa activity between 0.5 and 1.0 IU/ml. Bone density and bone turnover markers were measured. RESULTS: A total of 250 peak and trough low-molecular-weight heparin (LMWH) levels were obtained. Eighty-five percent of pregnancies (11/13) required an upward dosage adjustment. Trough levels were in the therapeutic range only 9% of the time, despite the maintenance of therapeutic peak levels. Bone resorption markers and density were unchanged in singleton pregnancies. CONCLUSION:Dalteparin dosing, based on weight alone, every 12 hours is inadequate to maintain most pregnant women in the therapeutic range throughout pregnancy as measured by anti-Xa activity. Trough levels are rarely in the therapeutic range, despite maintenance of therapeutic peak levels. These notable changes in low molecular weight heparin peak may explain reported failures in pregnancy.
Authors: Shannon M Bates; Ian A Greer; Saskia Middeldorp; David L Veenstra; Anne-Marie Prabulos; Per Olav Vandvik Journal: Chest Date: 2012-02 Impact factor: 9.410
Authors: Vera Regitz-Zagrosek; Christa Gohlke-Bärwolf; Annette Geibel-Zehender; Markus Haass; Harald Kaemmerer; Irmtraut Kruck; Christoph Nienaber Journal: Clin Res Cardiol Date: 2008-09 Impact factor: 5.460
Authors: Nancy L Shapiro; Michelle A Kominiarek; Edith A Nutescu; Aimee B Chevalier; Judith U Hibbard Journal: Pharmacotherapy Date: 2011-07 Impact factor: 4.705
Authors: Shannon M Bates; Anita Rajasekhar; Saskia Middeldorp; Claire McLintock; Marc A Rodger; Andra H James; Sara R Vazquez; Ian A Greer; John J Riva; Meha Bhatt; Nicole Schwab; Danielle Barrett; Andrea LaHaye; Bram Rochwerg Journal: Blood Adv Date: 2018-11-27