Thromb Haemost 2013; 109(04): 606-613
DOI: 10.1160/TH12-10-0771
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

The effect of different hormonal contraceptives on plasma levels of free protein S and free TFPI

Marjolein Raps
1   Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
,
Frans M. Helmerhorst
2   Department of Reproductive Medicine, Leiden University Medical Center, Leiden, the Netherlands
,
Kathrin Fleischer
3   Department of Obstetrics and Gynaecology, University Medical Center St. Radboud, Nijmegen, the Netherlands
,
Anders E. A. Dahm
4   Department of Haematology, Oslo University Hospital, and University of Oslo, Oslo, Norway
,
Frits R. Rosendaal
1   Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, the Netherlands
,
Jan Rosing
5   Department of Biochemistry, Maastricht University, Maastricht, the Netherlands
,
Pieter Reitsma
6   Department of Haemostasis and Thrombosis, Leiden University Medical Center, Leiden, the Netherlands
,
Per Morten Sandset
4   Department of Haematology, Oslo University Hospital, and University of Oslo, Oslo, Norway
,
Huib A. A. M. van Vliet
2   Department of Reproductive Medicine, Leiden University Medical Center, Leiden, the Netherlands
7   Department of Gynaecology Catharina Hospital, Eindhoven, the Netherlands
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Publikationsverlauf

Received: 24. Oktober 2012

Accepted after major revision: 14. Februar 2012

Publikationsdatum:
22. November 2017 (online)

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Summary

Use of combined oral contraceptives is associated with a three- to sixfold increased risk of venous thrombosis. Hormonal contraceptives induce acquired resistance to activated protein C (APC), which predicts the risk of venous thrombosis. The biological basis of the acquired APC resistance is unknown. Free protein S (PS) and free tissue factor pathway inhibitor (TFPI) are the two main determinants of APC. Our objective was to assess the effect of both hormonal and non-hormonal contraceptives with different routes of administration on free TFPI and free PS levels. We conducted an observational study in 243 users of different contraceptives and measured APC sensitivity ratios (nAPCsr), free TFPI and free PS levels. Users of contraceptives with the highest risk of venous thrombosis as reported in recent literature, had the lowest free TFPI and free PS levels, and vice versa, women who used contraceptives with the lowest risk of venous thrombosis had the highest free TFPI and free PS levels. An association was observed between levels of free TFPI and nAPCsr, and between free PS and nAPCsr. The effect of oral contraceptives on TFPI and PS is a possible explanation for the increased risk of venous thrombosis associated with oral contraceptives.