Why does pregnancy represent a special clinical setting with regard to the use of anticoagulants?
VTE is a frequent event in pregnancy. The risk of VTE is increased by 10 in pregnant women compared with non-pregnant women of child-bearing age. The highest risk period for VTE is during the post-partum period. The risk of VTE is higher after caesarean section than after vaginal delivery.
PE is the leading cause of maternal death in Western obstetric practice. The risk of recurrence is high: 1-15%
Demers and Ginsberg. Clin Chest Med 1992;13:645-56; Girling and de Swiet. Curr Opin Obstet Gynecol 1996;8:458-63; Toglia and Weg. N Engl J Med 1996;335:108- 14; Greer and Thomson. Baillieres Best Pract Res Clin Obstet Gynecol 2001;15:583- 603; Martinelli I. Thromb Haemost 2001;86:395-403; Heit, et al. Ann Intern Med 2005;143:697-706; Bates, et al. Chest 2004; 126(3 Suppl):627S-644S.
UFH may be used in pregnant women because:
VKA are generally not appropriate in pregnant women because:
Bates, et al. Chest 2004; 126(3 Suppl):627S-644S
Vitale, et al. J Am Coll Cardiol 1999;33:1637-41
Pregnancy may affect the pharmacokinetics of UFH or LMWH: it may be necessary to increase the dose, especially during the fi rst trimester. As the half-life of LMWH is shorter in pregnancy, twice-daily dosing is preferable over once-daily dosing, at least in the initial phase of the treatment of VTE.
Hawkins and Evans. Expert Opin Drug Saf 2005;4:583-90; Bates, et al. Chest 2004; 126(3 Suppl):627S-644S
LMWH are more advantageous than UFH in pregnant women because they do not cross the placenta and are safe in nursing mothers. Furthermore, compared with UFH, there is a reduced risk of heparin-induced thrombocytopenia, reduced risk of osteoporosis, efficacy and safety at least comparable, and less frequent monitoring.
Bates, et al. Chest 2004; 126(3 Suppl):627S-644S
With regard to fondaparinux (Arixtra®), in vitro data suggest that: it does not cross the placenta and its prolonged use should not result in osteoporosis.
Lagrange, et al. Thromb Haemost 2002;87:831-5
Handschin, et al. Br J Surg 2005;92:177-83
The heading provided below will take you to the corresponding abstract of the ACCP Evidence-Based Clinical Practice Guidelines (2008): Antithrombotic and Thrombolytic Therapy.