Semin Thromb Hemost 1999; 25(5): 497-502
DOI: 10.1055/s-2007-994957
Copyright © 1999 by Thieme Medical Publishers, Inc.

Detection of Decreased Response to Activated Protein C during Pregnancy by an Endogenous Thrombin Potential-Based Assay

Motoi Sugimura, Takao Kobayashi, Naohiro Kanayama, Toshihiko Terao
  • Department of Obstetrics and Gynecology, Hamamatsu University, School of Medicine, Hamamatsu, Japan.
Further Information

Publication History

Publication Date:
06 February 2008 (online)

Abstract

Pregnancy has been widely recognized as a predisposing risk factor for deep vein thrombosis (DVT). However, it still remains unclear why pregnant women without a history of familial thrombophilia or antiphospholipid syndrome (APS) have a higher incidence of DVT and pulmonary embolism (PE) during pregnancy and puerperium. We examined the activated protein C (APC) system in healthy pregnant women and in patients with the onset of DVT during puerperium. Sixty unselected Japanese pregnant women without a past or family history of thrombosis or APS and 3 Japanese women with DVT during puerperium were evaluated. Endogenous thrombin potential-ratio (ETP-r) was measured by determination of thrombin-alpha2,-macroglobulin complexes in thromboplastin-activated patient plasma. APC sensitivity ratio (APC-sr) was calculated by the determination of ETP-r in patient plasma in the presence and absence of APC (final concentration [conc.] 5.9 nM) to evaluate the functional APC anticoagulant activity. Mean APC-sr was significantly increased at 30 weeks' gestation (2.35 ± 0.72) and remained high during puerperium compared with the mean APC-sr in nonpregnant women (1.15 ± 0.63). Mean APC-sr in patients with DVT at the onset was significantly higher (3.57 ± 0.54) than mean APC-sr during puerperium was, indicating that the sensitivity to APC was reduced in the ETP-based assay. These data suggest a significant reduction in the functional sensitivity to APC associated with an increased risk of venous thrombosis during pregnancy.