Transactions of the Twenty-Fourth Annual Meeting of the Society for Maternal-Fetal MedicineA prospective trial that demonstrates that dalteparin requirements increase in pregnancy to maintain therapeutic levels of anticoagulation
Section snippets
Material and methods
Pregnant women diagnosed with an acute deep venous thrombosis (DVT) by duplex ultrasound examination or women who required therapeutic anticoagulation during pregnancy attending the High Risk Obstetric Practices at University of Colorado Health Sciences Center from 2001 through 2003 were study candidates. Informed consent was obtained by the principle investigator, and the study was approved by the Colorado Medical Institutional Review Board. Patients were excluded for pulmonary embolism, renal
Results
A total of 138 peak and 112 trough anti-Xa levels were obtained in 13 pregnancies in 12 women, for a total of 250 LMWH levels. The characteristics of the women who required therapeutic anticoagulation are described in Table I. All pregnancies were singleton, with the exception of a twin pregnancy in patient 5. Dalteparin was continued until near delivery or until pregnancy loss in all patients; the mean duration of dalteparin therapy was 16 weeks. All women had either an acute venous
Comment
This is the first prospective study in which peak (n = 138) and trough (n = 112) LMWH levels (anti-Xa activity) were monitored to determine whether a commonly used LMWH, dalteparin, would achieve peak therapeutic levels of anticoagulation in pregnancy when given every 12 hours at the recommended dosage per kilogram by the manufacturer. Our study demonstrates that in 85% of pregnant women, the dose of 100 U/kg every 12 hours was insufficient to achieve or maintain peak therapeutic levels of
Acknowledgments
We thank Pamela A. Lekahal for her significant contributions in the appropriate monitoring and follow-up of these patients and Kayla Carstens in the Special Endocrinology Laboratory for ensuring that all the N-Telopeptide measurements were collected appropriately and run in a timely fashion.
References (13)
- et al.
Changes in the pharmacokinetics of the low-molecular-weight heparin enoxaparin sodium during pregnancy
Am J Obstet Gynecol
(1999) - et al.
Low molecular weight heparin for the treatment of venous thromboembolism in pregnancy: a case series
BJOG
(2002) - et al.
Low molecular weight heparin (dalteparin) for the treatment of venous thromboembolism in pregnancy
BJOG
(2003) - et al.
Heparin levels to guide thromboembolism prophylaxis during pregnancy
Am J Obstet Gynecol
(1995) Contemporary laboratory monitoring of low molecular weight heparins
Thromb Hemost
(1995)- et al.
A prospective study of heparin-induced osteoporosis in pregnancy using bone densitometry
Am J Obstet Gynecol
(1994)
Cited by (0)
Supported by Pharmacia and Upjohn grant #524E-CVD-0042-0016.
Presented at the Twenty-Fourth Annual Meeting of the Society for Maternal Fetal Medicine, New Orleans, LA, February 2-7, 2004.
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