Sex hormone–binding globulin—A surrogate marker for the prothrombotic effects of combined oral contraceptives

Objective The purpose of this study was to investigate the plausibility of serum sex hormone–binding globulin (SHBG) concentration as a risk marker for venous thromboembolism (VTE) during use of combined oral contraceptives (COC). Study design This was a prospective, randomized cross-over study. Thirty-five women were treated with COCs containing the same amount of ethinyl estradiol and either levonorgestrel (LNG/EE) or desogestrel (DG/EE). Serum SHBG and markers of hemostasis were determined before and after 2 months on each treatment. Results SHBG increased significantly with both preparations. Treatment with DG/EE caused more pronounced prothrombotic changes in hemostatic parameters than LNG/EE. With both treatment regimens, there was a significant correlation between changes in resistance to activated protein C (APCr) and changes in plasma SHBG. Conclusion The correlation between SHBG and the well-established risk factor APCr might indicate the usefulness of SHBG as a risk marker for VTE during COC treatment