Venous thromboembolism and the pill. The WHO technical report on cardiovascular disease and steroid hormone contraception: state-of-the-art. World Health Organization

Effects of conventional or extended-cycle regimen of an oral contraceptive containing 30 mcg ethinylestradiol and 2 mg dienogest on various hemostasis parameters

BACKGROUND

The study was conducted to investigate the effect of a combined oral contraceptive (COC) containing 30 mcg ethinylestradiol and 2 mg dienogest with two different regimens on various hemostasis variables.

STUDY DESIGN

Hemostatic parameters were measured in 59 women treated with a monophasic COC containing 30 mcg ethinylestradiol and 2 mg dienogest (EE/DNG) either conventionally (13 cycles with 21 days of treatment+7 days without hormones) or with an extended-cycle regimen (4 extended cycles with 84 days of continuous administration of EE/DNG, followed by a hormone-free interval of 7 days). Blood samples were taken on Days 21-26 of the preceding control cycle and on Days 19-21 of the 3rd and 13th conventional cycle or on Days 82-84 of the first and fourth extended cycle.

RESULTS

After 3 and 12 months, significant increases in fibrinogen (20%), factor VII antigen (50-60%), factor VII activity (45%), activated factor VII (30-45%) and factor VIII activity (10-20%) occurred in both treatment regimens. In both groups, there was a small but significant decrease in the level and activity of antithrombin, a 20-25% decrease in total and free protein S and a 15-20% rise in the level and activity of protein C, but no significant change of the thrombin-antithrombin complex. A significant over-time rise by about 25% of prothrombin fragment 1+2 occurred only in the extended-cycle group, but this effect did not differ significantly from that observed during conventional treatment. Plasminogen was elevated by 50% in both groups, while tissue-plasminogen activator (t-PA) activity rose by 15% in the conventional group and by 25-30% in the extended-cycle group. In both groups, t-PA antigen was reduced by about 30% and plasminogen activator inhibitor-1 by 40-60%. The levels of the plasmin-antiplasmin complex rose by 30-40% and those of D-dimers by 20-55%. The prothrombin time was slightly increased and the activated partial thromboplastin time was slightly decreased.

CONCLUSION

In general, these results were in agreement with those observed during treatment with other COCs. The study demonstrated that during conventional and extended-cycle treatment with EE/DNG, a steady-state in the effects on hemostasis variables was reached within 3 months, and that the effects observed after 3 and 12 months of treatment did not substantially differ between conventional and extended-cycle regimen.

Effect of four oral contraceptives on hemostatic parameters

This is the first double-blind, controlled, randomized study comparing the effect of different estrogen components in oral contraceptives (OCs) on hemostasis variables. Four groups of 25 women each were treated for six cycles with monophasic combinations containing 21 tablets with either 30 microg ethinylestradiol (EE) + 2 mg dienogest (DNG) (30EE/DNG), 20 microg EE + 2 mg DNG (20EE/DNG), 10 microg EE + 2 mg estradiol valerate (EV) + 2 mg DNG (EE/EV/DNG) or 20 microg EE + 100 microg levonorgestrel (LNG) (EE/LNG). Blood samples were taken on Days 21-26 of the control cycle and on Days 18-21 of the first, third and sixth treatment cycle. Treatment with all four OCs caused an increase in levels of fibrinogen, prothrombin fragment 1+2, D-dimer, plasminogen, plasmin-antiplasmin complex and an increase in protein C activity, a decrease in antithrombin activity, tissue-plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI), and a slight decrease in the sensitivity to activated protein C, but no significant change in that of the thrombin-antithrombin complex. In users of the DNG-containing OCs, the reduction in total and free protein S, and in t-PA and PAI was dependent on the EE dose, while factor VII activity was elevated, but not significantly different from EE/LNG. The results are in agreement with those of previous studies. The effects of EE/EV/DNG on total and free protein S and on t-PA and PAI were lower than those of 20EE/DNG, suggesting that the impact of 2 mg EV on several hemostasis variables is less than that of 10 microg EE. The results show an antagonistic effect of LNG on the EE-induced rise of factor VII activity and fragment 1+2 and on the EE-dependent reduction of total and free protein S.

Estrogen-induced cardiorenal protection: potential cellular, biochemical, and molecular mechanisms

A number of cellular and biochemical processes are involved in the pathophysiology of glomerular and vascular remodeling, leading to renal and vascular disorders, respectively. Although estradiol protects the renal and cardiovascular systems, the mechanisms involved remain unclear. In this review we provide a discussion of the cellular, biochemical, and molecular mechanisms by which estradiol may exert protective effects on the kidneys and vascular wall. In this regard, we consider the possible role of genomic vs. nongenomic mechanisms and estrogen receptor-dependent vs. estrogen receptor-independent mechanisms in mediating the protective effects of estradiol on the renal and cardiovascular systems.