Increased levels of activated factor VII and decreased plasma protein S activity and circulating thrombomodulin during use of oral contraceptives.

ABSTRACT

PIP: The effect of oral contraceptive (OC) treatment on selected factors involved in the activation and inhibition of blood coagulation was measured in a prospectively randomized parallel-group centralized-center study. These were circulating activated factor VII (cFVIIa) as well as plasma protein S activity and circulating thrombomodulin (cTM). In addition to other coagulation variables these parameters were measured during treatment with 3 low-estrogen formulations containing different gestagen components (norgestimate, gestodene). 60 healthy women 19-37 years old were included. The women in Group I used Cileste tablets containing 35 mcg ethinyl estradiol (EE) and 250 mcg norgestimate (NG). Group II women used the 3-phase preparation Tri-Cileste containing EE and different doses of NG; and Group II women used the 3-phase preparation Triodena containing different doses of EE and gestodene (GS). 21 days on treatment were followed by 7 days off of treatment before the next cycle was started. Participants were treated for 6 cycles. Blood samples were obtained during the luteal phase before treatment and on days 18-22 of the 3rd and 6th treatment cycle. The plasma levels of various coagulation parameters, such as fibrinogen (Cileste, Tri-Cileste p 0.05; Triodena p 0.0005); fibrin-split product D-Dimer (Cileste p 0.05; Tri-Cileste, Triodena p 0.005), prothrombin fragment F1+2 (Cileste p 0.0005); Tri-Cileste, Triodena p 0.05); Factor VII antigen (Cileste, Triodena p 0.0005; Tri-Cileste p 0.005); FVII clotting activity (Cileste p 0.0005; Tri-Cileste p 0.05; Triodena p 0.005), and activated factor VII (Cileste p 0.0005; Tri-Cileste p 0.05; Triodena p 0.005) were significantly higher during the 3rd treatment cycle compared with the pretreatment values. A significant decrease was also found in the plasma levels of total and free protein S antigen (total protein S: Cileste p 0.05; Tri-Cileste, Triodena p 0.005; free protein S: Cileste, Tri-Cileste p 0.0005; Triodena p 0.05) and circulating thrombomodulin (Cileste p 0.05; Tri-Cileste p 0.0005; Triodena p 0.005).