ABSTRACT

Rad, Mandana, Cornelis Kluft, Joël Ménard, Jacobus Burggraaf, Marieke L. de Kama, Piet Meijer, Irving Sivin, and Régine L. Sitruk-Ware. 2006. "Comparative effects of a contraceptive vaginal ring delivering a nonandrogenic progestin and continuous ethinyl estradiol and a combined oral contraceptive containing levonorgestrel on hemostasis variables," American Journal of Obstetrics and Gynecology 195(1): 72–77.

Objective
This study aimed to compare the effects on hemostasis variables of a contraceptive vaginal ring with those of an oral contraceptive.

Study design
Twenty-three and 22 healthy premenopausal women were randomized to the contraceptive vaginal ring (150 μg Nestorone and 15 μg ethinyl estradiol) or Stediril 30 during three cycles. Analysis of covariance was performed with baseline values as covariate.

Results
The contraceptive vaginal ring changed most hemostasis variables similarly but raised (95% confidence intervals of percent treatment differences) Factor VIIt (28 percent to 49 percent), extrinsic activated protein C resistance (14 percent to 65 percent), and sex hormone–binding globulin (117 percent to 210 percent) and lowered Protein S (−32 percent to −16 percent) and the global activated partial thromboplastin time-based activated protein C resistance (−12 percent to −2 percent) more than the oral contraceptive.

Conclusion
The contraceptive vaginal ring affected some measured hemostasis variables and sex hormone–binding globulin differently from the oral contraceptive, most likely because of difference in androgenicity of the progestins. The results suggest that the contraindications for oral contraceptive use would also apply to the tested contraceptive vaginal ring.

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