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Abstract

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 
Rad,Mandana; Kluft,Cornelius; Menard,Joel; Burggraaf,Jacobus; de Kam,Marieke L.; Meijer,Piet; Sivin,Irving; Sitruk-Ware,Regine
American Journal of Obstetrics and Gynecology 195(1): 72-77
Publication date: 2006



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 mug Nestorone and 15 mug ethinyl estradiol) or Stediril 30 during 3 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% to 49%), extrinsic activated protein C resistance (14% to 65%), and sex hormone-binding globulin (117% to 210%) and lowered Protein S (-32% to -16%) and the global activated partial thromboplastin time-based activated protein C resistance (-12% to -2%) 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.