APC resistance and third-generation oral contraceptives: Acquired resistance to activated protein C, oral contraceptives and the risk of thromboembolic disease

The Predictability of Factor V Leiden (FV:Q506) Gene Mutation via Clotting-Based Diagnosis of Activated Protein C Resistance

After the discovery of activated protein C resistance (APCR) due to factor V Leiden mutation and the causal relationship of the phenomenon with clinical thromboembolism, a wide variety of functional clotting-based assays were developed for testing of APCR in relation to the specific DNA-based analysis of FV:Q506 Leiden. The aim of this study is to assess a clotting-based APCR assay using procoagulant crotalidae snake venom with respect to the sensitivity, specificity, and predictability for the presence of the factor V Leiden mutation. APCR testing and factor V DNA analyses have been performed concurrently on 319 patient specimens. APCR values of the patients with homozygous factor V Leiden mutation (70.4±13.5 s) were significantly lower (p<0.001) in comparison to the subjects with the heterozygous mutation (87.6±13.4 s). The assay is highly sensitive (98.7%) and specific (91.9%) for the screening of factor V Leiden mutation. The sensitivity and specificity of the APCR testing reached to 100% below the cut-off value of 120 s among the patients with homozygous factor V Leiden mutation. Therefore, this method could help the desired effective optimal screening strategy for the laboratory search of hereditary thrombophilia focusing on the diagnosis of APCR due to FV:Q506.

Venous thrombosis and oral contraceptives: current status

The use of oral contraceptives is associated with an increased risk of venous thrombosis. It is now generally accepted that women who use oral contraceptives that contain so-called third-generation progestins (desogestrel or gestodene) are exposed to a twofold higher risk of venous thrombosis than women who use oral contraceptives that contain the second-generation progestin levonorgestrel. Coagulation studies demonstrated that oral contraceptives increase the plasma level of prothrombin, decrease the level of protein S and induce acquired activated protein C resistance. The changes in hemostatic parameters can explain why women who use oral contraceptives are exposed to an increased risk of venous thrombosis and why the risk is further increased in third-generation oral contraceptive users.

The role of combined oral contraceptives in the management of acne and seborrhea

Acne and seborrhea (or facial oiliness) are related androgenic skin disorders which affect a high proportion of women after menarche. They can have a negative effect on psychological well-being and social life. Androgens play an important role in the pathogenesis of acne through the stimulation of sebum secretion, increasing sebaceous gland size and possibly through follicular hyperkeratinization. Conversely, estrogens decrease sebum production by suppressing gonadotropin release and androgen production and increasing sex hormone binding globulin production. One of the treatment options for these conditions is hormonal therapy, especially for women who require contraception. The effect of combined oral contraceptives in androgenic skin disorders depends on their estrogen:progestogen balance and on the antiestrogenic activity of the progestogen component. Improved understanding of what women value about oral contraceptives suggests that the choice of product should be tailored as much as possible to the individual. Several combined oral contraceptives containing new-generation progestogens (e.g. desogestrel, gestodene) or progestational antiandrogens (e.g. cyproterone acetate, chlormadinone acetate) have demonstrated efficacy in the treatment of women with acne, although comparisons between trials are difficult because of differing endpoints. Seborrhea has been less well studied, but the few studies that are available show an improvement in women with this condition using combined oral contraceptives.

Combined hormonal contraception and venous thromboembolism

This review provides an update of knowledge regarding venous thromboembolism (VTE) and combined hormonal contraceptives (CHCs) in the light of new progestins and new administration routes for CHCs. Practical recommendations are also offered. The association between the use of combined oral contraceptives (COCs) and an increased risk of VTE has been known about for many years, it being related mainly to the dose of oestrogen; however, recent research has also shown the influence of the type of progestin. When compared to COCs containing levonorgestrel or norethisterone, those containing desogestrel or gestodene present a two-fold greater risk of VTE; for COCs containing cyproterone acetate, the risk is four-fold greater, while there are no or insufficient data for those containing norgestimate, chlormadinone acetate or drospirenone. With regard to the contraceptive patch, the available data suggest that the risk of VTE is similar to that observed with COCs. There are no data concerning vaginal rings. The greatest risk of COC-associated VTE occurs during the first year of use, thus suggesting the existence of a predisposing condition, such as being a carrier of a thrombogenic mutation with which the COCs would exert a synergistic effect. Routine screening for such conditions is not justified. Changes in haemostatic variables produced by COCs, for example, acquired resistance to protein C, could be linked to VTE, although it has yet to be demonstrated that such alterations are related to a clinical risk of VTE among COC users. At present there are no laboratory tests able to detect an increased risk of VTE in asymptomatic women. The key procedures in terms of ensuring the safe use of this contraceptive method are a full clinical, personal and family history, in order to evaluate risk factors for VTE and cardiovascular disease, along with the recording of blood pressure and body mass index prior to the prescription of COCs.

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.