The effect of the levonorgestrel-releasing intrauterine system on the resistance to activated protein C (APC).

Abstract

Exogenously administered estrogens and progestogens as during combined oral contraceptive use increase the risk of venous thrombosis. The thrombin generation-based APC resistance assay is a global coagulation test that enables quantification of the net prothrombotic effect of combined oral contraceptives and that predicts the risk of thrombosis. The thrombotic risk of the levonorgestrel-releasing intrauterine system is unknown. It was the objective of this study to evaluate the thrombotic risk by comparing the APC resistance before and after insertion of a levonorgestrel-releasing or a copper-containing intrauterine device. We measured normalized APC-sensitivity ratios (nAPCsr) before and three months after insertion of the levonorgestrel-intrauterine system in 56 women and the copper-intrauterine device in 18 women. In women without hormonal contraceptive use or a pregnancy in the three months before collection of the baseline samples, nAPCsr were lower three months after insertion of the levonorgestrel-intrauterine system than at baseline (difference -0.29; 95% CI -0.04 to -0.53) and hardly changed after insertion of the copper-intrauterine device (difference -0.11; 95% CI -1.03 to 0.82). In women who switched from a combined oral contraceptive to the levonorgestrel-system the difference was more pronounced (-1.48; 95% CI -0.85 to -2.11). In this study we observed that the levonorgestrel-intrauterine system decreases the resistance to APC which indicates that the levonorgestrel-intrauterine system does not have a prothrombotic effect.

• Authors: Huib A A M van Vliet, Svetlana N Tchaikovski, Frits R Rosendaal, Jan Rosing, Frans M Helmerhorst
• Journal: Thrombosis and haemostasis (Thromb Haemost) Vol. 101 Issue 4 Pg. 691-5 (Apr 2009) ISSN: 0340-6245 [Print] Germany
• PMID: 19350113 (Publication Type: Clinical Trial, Journal Article)

Chemical References

• Biomarkers
• Contraceptives, Oral, Combined
• Levonorgestrel
• Thrombin

Topics

• Activated Protein C Resistance (blood, etiology, genetics)
• Adult
• Biomarkers (blood)
• Contraceptives, Oral, Combined (adverse effects)
• Female
• Genetic Predisposition to Disease
• Humans
• Intrauterine Devices, Copper (adverse effects)
• Intrauterine Devices, Medicated (adverse effects)
• Levonorgestrel (adverse effects)
• Middle Aged
• Pedigree
• Risk Assessment
• Risk Factors
• Thrombin (metabolism)
• Time Factors
• Venous Thrombosis (blood, etiology, genetics)
• Young Adult