Oral Contraceptive and Hemostasis Study Group. The effects of seven monophasic oral contraceptive regimens on hemostatic variables: conclusions from a large randomized multicenter study

Longitudinal profile of estrogen-related thrombotic biomarkers after cessation of combined hormonal contraceptives

ABSTRACT

The persistence of risk of venous thromboembolism (VTE) due to combined hormonal contraceptives (CHCs), after their cessation, is unknown but important to guide clinical practice. The objective of this prospective cohort study was to define the time until normalization of estrogen-related thrombotic biomarkers after CHC cessation. We enrolled women aged 18 to 50 years who had decided to stop their CHC, excluding those with a personal history of VTE, anticoagulation, or pregnancy. The study started before cessation of CHC, with 6 visits afterwards (at 1, 2, 4, 6, and 12 weeks after cessation). Primary outcomes were normalized sensitivity ratios to activated protein C (nAPCsr) and to thrombomodulin (nTMsr), with sex hormone-binding globulin (SHBG) as a secondary end point. We also included control women without CHC. Among 66 CHC users, from baseline until 12 weeks, average levels of nAPCsr, nTMsr, and SHBG decreased from 4.11 (standard deviation [SD], 2.06), 2.53 (SD, 1.03), and 167 nmol/L (SD, 103) to 1.27 (SD, 0.82), 1.11 (SD, 0.58), and 55.4 nmol/L (SD, 26.7), respectively. On a relative scale, 85.8%, 81.3%, and 76.2% of the decrease from baseline until 12 weeks was achieved at 2 weeks and 86.7%, 85.5%, and 87.8% at 4 weeks after CHC cessation, respectively. Levels were not meaningfully modified throughout the study period among 28 control women. In conclusion, CHC cessation is followed by a rapid decrease in estrogen-related thrombotic biomarkers. Two to 4 weeks of cessation before planned major surgery or withdrawal of anticoagulants in patients with VTE appears sufficient for the majority of women. The trial is registered at www.clinicaltrials.gov as #NCT03949985.

Protein C and protein S deficiencies are associated with increased risk of deep vein thrombosis in pregnant women using oral contraceptives

BACKGROUND

Oral contraceptives are commonly taken by women and are known to increase the risk of venous thromboembolism (VTE).

OBJECTIVE

The aim of this study was to investigate the association between oral contraceptive use and natural anticoagulants, that is, protein C (PC), protein S (PS), and antithrombin in pregnant women with deep vein thrombosis (DVT).

MATERIALS AND METHODS

This case-control study was conducted on 330 pregnant women, that is, cases 165 (who used oral contraceptives) and controls 165 (who did not use oral contraceptives). The levels of PC, PS, and antithrombin were measured and compared between the two groups. The use of different types of oral contraceptives and their association with DVT and PC and PS were also analyzed.

RESULTS

The study found that women with DVT had significantly lower levels of PC and PS compared with controls ( P  < 0.001). However, no significant difference was found in the levels of AT. Among the different types of oral contraceptives, first-generation progestin pills including Ethynodiol Diacetate, Norethindrone Acetate, Norethynodrel, and second-generation oral contraceptives (Lynestrenol, Levonorgestrel and Norgestrel) were not found to be associated with lower levels of PC and AT while Desogestrel, Norgestimate, and Gestodene (third-generation) were associated with lower levels of PS.

CONCLUSION

This study suggests that the use of contraceptives, particularly those containing Desogestrel, Norgestimate, and Gestodene, may be associated with a higher risk of thrombosis because of the associated lower levels of PS. Monitoring anticoagulant levels is crucial in preventing DVT in this population.

Building the foundation for a community-generated national research blueprint for inherited bleeding disorders: research to advance the health of people with inherited bleeding disorders with the potential to menstruate

BACKGROUND

People who have or had the potential to menstruate (PPM) with inherited bleeding disorders (BD) face particular challenges receiving appropriate diagnosis and care and participating in research. As part of an initiative to create a National Research Blueprint for future decades of research, the National Hemophilia Foundation (NHF) and American Thrombosis and Hemostasis Network conducted extensive all-stakeholder consultations to identify the priorities of PPM with inherited BDs and those who care for them.

RESEARCH DESIGN AND METHODS

Working group (WG) 4 of the NHF State of the Science Research Summit distilled community-identified priorities for PPM with inherited BDs into concrete research questions and scored their feasibility, impact, and risk.

RESULTS

WG4 identified important gaps in the foundational knowledge upon which to base optimal diagnosis and care for PPM with inherited BDs. They defined 44 top-priority research questions concerning lifespan sex biology, pregnancy and the post-partum context, uterine physiology and bleeding, bone and joint health, health care delivery, and patient-reported outcomes and quality-of-life.

CONCLUSIONS

The needs of PPM will best be advanced with research designed across the spectrum of sex and gender biology, with methodologies and outcome measures tailored to this population, involving them throughout.

Combined oral contraceptives containing estradiol valerate vs ethinylestradiol on coagulation: A randomized clinical trial

INTRODUCTION

Contraceptives containing ethinylestradiol (EE) induce changes in the coagulation system and are associated with a risk of venous thromboembolism. However, studies comparing the effects of combined oral contraceptives containing EE and low-potency estrogens (ie, estradiol [E₂ ] and estradiol valerate [EV]) on coagulation biomarkers are limited. This study represents secondary outcomes of a randomized trial comparing combined oral contraceptives containing EV + dienogest (DNG), EE + DNG, and DNG alone on selected coagulation biomarkers. We could compare the specific effects of the different estrogen components owing to the inclusion of preparations containing the same progestin.

MATERIAL AND METHODS

We enrolled 59 healthy, 18- to 35-year-old, non-smoking women, of whom three discontinued. The participants were randomly allocated to 9 weeks of continuous treatment with EV 2 mg + DNG 2-3 mg (n = 20), EE 0.03 mg + DNG 2 mg (n = 20), or DNG 2 mg (n = 19). Blood samples were collected at baseline and after 9 weeks. We assessed coagulation in vitro by thrombin generation using the Calibrated Automated Thrombogram. Thrombin generation was evaluated by lag time, time to thrombin peak, thrombin peak, and endogenous thrombin potential in response to tissue factor (1 pm). In vivo coagulation assessment was based on levels of prothrombin fragment 1 + 2 (F1 + 2) (thrombin generation) and D-dimer (fibrin turnover).

CLINICAL TRIAL REGISTRATION

NCT02352090.

RESULTS

Lag time and time to thrombin peak remained unaltered after exposure to EV + DNG, whereas EE + DNG shortened both lag time (mean percentage change -24%, 95% confidence interval [CI] -32% to -15%; p < 0.01) and time to thrombin peak (-26%, 95% CI -37% to -16%; p < 0.01). EV + DNG induced lower thrombin peak and endogenous thrombin potential than EE + DNG (peak; +45%, 95% CI 22%-67% vs +147%,95% CI 96%-198%; p < 0.01, and endogenous thrombin potential; +26%, 95% CI 15%-38% vs +64%, 95% CI 51%-76%; p < 0.01). Median F1 + 2 levels remained unchanged with EV + DNG (p = 0.22) but increased within normal ranges with EE + DNG (from 152 pmol/L, 95% CI 127-206] pmol/L to 194 pmol/L, 95% CI 149-250 pmol/L, p = 0.04). The within-group change in D-dimer levels was not significant in any of the groups. DNG alone did not affect these biomarkers.

CONCLUSIONS

Both in vitro and in vivo thrombin generation was lower after exposure to EV + DNG compared with EE + DNG. The lower thrombin generation measures after treatment with EV + DNG indicate less enhancement of coagulation potential and suggest that EV may be favorable to EE as a component of combined oral contraceptives.

The paradigm of norgestimate: a third-generation testosterone-derivative progestin with a peripheral anti-androgenic activity and the lowest risk of venous thromboembolism

INTRODUCTION

Norgestimate (NGM) is a testosterone derivative with peculiar receptor activities.

AREAS COVERED

This is a narrative review of the available data on the pharmacotherapy of NGM in combined hormonal contraceptives (CHCs) in terms of contraceptive efficacy, venous thromboembolism (VTE) risk, safety, tolerability and bleeding patterns. A comprehensive literature review was conducted in August 2020 using PubMed with the keyword 'norgestimate'.

EXPERT OPINION

NGM shows a mild estrogenic activity associated with anti-mineralocorticoid and anti-androgenic properties, largely responsible for the cardiovascular safety profile. The anti-androgenic property depends on the androgen receptor (AR) nuclear translocation (AR trafficking and its subnuclear distribution), the inhibition of 5α-reductase activity (it possesses higher activity compared to other available progestins), and the increase on sexual hormone binding globulin (SHBG) levels if combined with an estrogenic counterpart. NGM is one of the molecules that best modulates the power of ethinyl-estradiol on the thromboembolic risk, being associated with the lowest VTE risk between different CHCs. NGM has the advantage of retaining peripheral anti-androgenic activity, demonstrated by the impact on lipid and glucose metabolism, and it should be preferred if compared with other similar progestins of the same class of risk which are much more androgenic, such as levonorgestrel.

Oral Contraceptives and Venous Thromboembolism: Focus on Testing that May Enable Prediction and Assessment of the Risk

Combined oral contraceptives (COCs) induce several changes in the levels of coagulation factors. The levels of procoagulant factors are often increased, while levels of anticoagulant factors are decreased. Fibrinolysis is also affected, even if the effect seems to be more counterbalanced by opposite regulation of profibrinolytic and antifibrinolytic factors. These effects on hemostasis are more pronounced with third- or fourth-generation COC compared with second-generation COC. Venous thromboembolism (VTE) risk increases when multiple risk factors, including genetic and environmental, are present simultaneously. COC use causes changes in coagulation that modify the prothrombotic state induced by preexisting hemostatic alterations in a supra-additive manner. Therefore, testing appears to be of importance not only before implementing COC but also to monitor any potential thrombogenicity induced by COC therapy. Inherited genetic factors, such as factor V Leiden, G20210A prothrombin mutation, antithrombin, protein C or protein S deficiencies, non-O blood group, as well as CYP2C9*2 and the rs4379368 mutations, have all been identified as genetic predictive risk factors of VTE in women. Nevertheless, the screening of these genetic biomarkers is not capable of assessing the phenotypic expression of the risk. This review will focus on the different options for screening the thrombogenic status in this population. Specific attention will be given to the endogenous thrombin potential-based activated protein C resistance, a test aiming at assessing the thrombogenicity induced by hormonal therapies and inherited or acquired thrombophilia.

Proof of concept of a new scale for the harmonization and the standardization of the ETP-based APC resistance

BACKGROUND

The evaluation of the activated protein C resistance (APCr) based on the endogenous thrombin potential (ETP) is recommended during the development of steroid contraceptives. Results are usually expressed as "normalized APC sensitivity ratio" (nAPCsr) using a reference plasma that should achieve an ETP ratio of 0.1 in presence of exogenous APC. Because of the interassay variability, achieving exactly an ETP ratio of 0.1 in each run is almost impossible, which significantly affects the theoretical 0-10 scale of nAPCsr.

OBJECTIVES

To compare the nAPCsr to the nAPCsr10 , a newly proposed method to express the degree of APC resistance.

METHODS

Individual plasma samples (n = 854) were analyzed to compare nAPCsr and nAPCsr10 . These values were obtained using the validated ETP-based APCr assay.

RESULTS

The Spearman correlation between nAPCsr and nAPCsr10 had a coefficient of 0.99. Linear regression showed the following equation y = 0.9315*x + 0.03942 (r2  = .97). When differences (nAPCsr10 - nAPCsr) were plotted against nAPCsr10 , the mean difference equaled 0.16% or 4.95%. The correction obtained with the use of the nAPCsr10 showed that the results of the nAPCsr were statistically different (P < .0001).

CONCLUSIONS

This new scale provides a harmonization and normalization of the nAPCsr. Results show a better reproducibility with the nAPCsr10 . It avoids the additional variability and the unharmonized scale introduced by the use of a reference plasma. This adapted method for the calculation of the APC resistance could provide the regulatory and scientific bodies with more reproducible and harmonized evaluations.

Hormonal contraceptives and the risk of ischemic stroke in women with migraine: a new international consensus

The paper is devoted to the safe use of hormonal contraception in women with migraine, an urgent interdisciplinary problem daily faced by gynecologists, neurologists, and specialists in headache diagnosis and treatment. It gives information on the prevalence of migraine, the risk of ischemic stroke and other cardiovascular disorders in women with different types of migraine, including those receiving contraception and hormone replacement therapy. The paper presents the main provisions of the new interdisciplinary consensus «Hormonal contraceptives and the risk of ischemic stroke in women who have migraine», which are recommended to be taken into account by specialists of any profile when prescribing hormonal therapy to women with migraine in order to avoid cardiovascular events.

Thrombin generation measurement using the ST Genesia Thrombin Generation System in a cohort of healthy adults: Normal values and variability

BACKGROUND

Thrombin generation (TG) assays evaluate the balance between pro- and anticoagulant forces, to better assess bleeding and thrombotic risks. Although TG readouts obtained with the calibrated automated TG have been investigated in multiple clinical conditions, TG still needs standardization and clinical validation. The automated TG instrument ST Genesia® (STG, Stago, Asnières-sur-Seine, France) provides a normalization of TG parameters based on a reference plasma aiming to reduce the interlaboratory variability and the variability between different measurement runs.

OBJECTIVES

To evaluate STG in a group of healthy adults.

METHODS

Reference intervals in healthy adults and variability of the new standardized reagents for bleeding (BleedScreen) and thrombophilic (ThromboScreen) conditions were determined using STG.

RESULTS

TG was measured in platelet-free plasma (PFP) samples of 123 healthy adults. Reference intervals were determined for TG parameters. Intra- and interassay coefficients of variation were calculated on quality controls and PFP samples from healthy adults. Oral contraception (OC) possibly influenced TG parameters, resulting in a higher median and a broader reference interval for peak height and endogenous thrombin potential (ETP) in women aged 20 to 49 years than in all other sex and age categories. Therefore, we propose the following reference interval categories: men, women aged <50 years not using OC, women aged <50 years using OC, and women aged ≥50 years. Normalization was effective to reduce the interassay variability of quality controls for ETP (BleedScreen assay), and peak height and ETP (ThromboScreen assay without thrombomodulin), but had little impact on PFP sample variability.

CONCLUSION

STG appears suitable for accurate measurement of TG in healthy adults.

Clinical and laboratory manifestations of the prothrombin gene mutation in women of reproductive age

Research objective

To research the association of prothrombin (factor II) activity given the prothrombin G20210A mutation carriage with its clinical manifestations as thrombotic complications.

Materials and methods

A prospective clinical cohort study of 290 women of reproductive age was conducted. Two cohort groups were identified: the study group of 140 patients with prothrombin mutation G20210A genotype and the control group of 150 women with G20210G genotype.

Results

The prothrombin G20210A mutation carriage is associated with the risk of thrombotic complications compared to the wild G20210G type (RR =17.1; p<0.0001) and is characterized by thrombosis localized both in the venous (66.7%) and arterial (33.3%) vascular pools. The threshold value of prothrombin activity (174.8%) for G20210A genotype was calculated, making it possible to conclusively predict the risk of thrombotic events with the accuracy of 90.4%.

Conclusion

The phenotypic manifestation of the prothrombin G20210A mutation in the form of venous and arterial thromboses in women of reproductive age is associated with a super-threshold increase in prothrombin (factor II) activity, which makes it possible to stratify the patients into the group of high risk of thromboses.

Effects of low-dose combined oral contraceptives and protein S K196E mutation on anticoagulation factors: a prospective observational study

The association between low-dose combined oral contraceptives (COCs) and anticoagulation factors in Japanese women has been rarely studied. A total of 394 Japanese women with a new beginning cycle of COC use were enrolled, of whom 335 women visited the clinic within 4 weeks after starting the first cycle of COC. Visits occurred in the active phase (272 women) and the placebo phase (63 women). Free protein S (PS) antigen and activity levels and antithrombin activity levels decreased significantly in both the active and placebo phase groups. Protein C (PC) activity levels increased significantly in both groups. Larger reductions in free PS antigen and activity levels occurred with COC comprising either 30 µg ethinylestradiol/desogestrel or 20 µg ethinylestradiol/drospirenone than that comprising 35 µg ethinylestradiol/norethisterone. In four women with the Japanese-specific PS K196E mutation, mean PS activity was 65% before COC use and 57% during COC use, indicating further decrease with COC use. In conclusion, decreased antigen and activity levels of PS and antithrombin and increased activity levels of PC were observed even during the first cycle of low-dose COC use. The effects on PS and PC activities were also observed in the hormone-free interval.

Impact of progestogens on hemostasis

Combined hormonal contraception containing estrogen and progestogen and postmenopausal hormone therapy with estrogen ± progestogen are reported risk factors for venous thrombosis. The thrombotic risk varies by estrogen dose and type of progestogen. Estrogen combined with "newer generation" progestogens in combined oral contraceptives may have higher thrombotic risk than estrogen combined with older generation progestogens. Among postmenopausal women thrombotic risk also varies by type of hormone and mode of delivery. Although the risk of thrombosis with the different hormonal compounds is uncertain, it has definitely been attributed to the pharmacological effect of the hormones on hemostasis. Animal and cell culture studies have demonstrated the pharmacodynamics of progestogens with respect to hemostasis. Extrapolation from these studies to clinical conditions and further to clinical end points such as cardiovascular disease is, however, controversial. Few clinical studies have focused on the effect of progestogen only therapy on the hemostatic system in vivo. Most of the current knowledge regarding the in vivo effect of progestogens on hemostasis is obtained from studies with combined contraceptives. These results obviously reflect the combined influence of both estrogen and progestogen on hemostasis, and extrapolation to progestogen-only conditions is challenging. This paper discusses the pharmacodynamics of progestogens in relation to the hemostatic system, addressing results obtained in animal and cell culture studies and in clinical studies employing progestogen-only and combined oral contraceptives. The compiled results suggest that the major effect of progestogens on hemostasis is related to alterations in platelet function and the tissue factor pathway of coagulation. More studies focusing on these topics are warranted.

Hemorheological mechanisms for increased thrombosis in subjects using gestodene

There are several possible mechanisms by which combined oral contraceptives (COC) use increase venous thromboembolism (VTE) risk. Melodene® is a monophasic COC containing the third-generation progestin Gestodene (GSD), which is associated with increased risk of VTE. Therefore, the aim of this study was to investigate the possible alterations in viscoelastic parameters of whole blood and plasma clots along with the biophysical characteristics of erythrocytes and specifically fibrin fibers in females using a COC containing GSD. GSD appeared to have a significant impact on the biophysical characteristics of fibrin fiber networks. When GSD is combined with ethinylestradiol the viscoelastic properties of whole blood clots tend to become more prothrombotic. The alterations to and aggregation of erythrocytes accompanied with spontaneous formation of a fibrin "blanket" provides a possible mechanism for the increased occurrence of "red" clots, which can lead to occlusions in the vascular system. Thus, the increased risk of VTE associated with these COCs can be attributed to these erythrocyte-and-fibrin-rich-clots occluding venous vessels. However, our findings also propose that these changes to the biophysical properties of both erythrocytes and fibrin, specifically spontaneous expansion of deformed fibrin networks, can also occlude vessels in the microcirculation, which could have lasting, subclinical complications for female users. We recommend that a thorough risk assessment, with specific focus on coagulation and other factors affecting fibrin formation, be done for each female before prescribing a GSD-containing COC. Females that "qualify" then need to be monitored on a regular basis to lower the risk of thrombotic events. RESEARCH HIGHLIGHTS: Gestodene in combination with ethinyl estradiol significantly impacts the biophysical characteristics of erythrocytes and fibrin fiber networks. These changes, specifically spontaneous expansion of deformed fibrin networks, can occlude vessels in the microcirculation, which could have lasting, subclinical complications for the female user. The changes observed for specifically erythrocytes and fibrin show that the hormone formulation investigated contribute to a thrombogenic profile for female users.

Sex-specific performance of pre-imaging diagnostic algorithms for pulmonary embolism

Essentials Decision rules for pulmonary embolism are used indiscriminately despite possible sex-differences. Various pre-imaging diagnostic algorithms have been investigated in several prospective studies. When analysed at an individual patient data level the algorithms perform similarly in both sexes. Estrogen use and male sex were associated with a higher prevalence in suspected pulmonary embolism.

SUMMARY

Background In patients suspected of pulmonary embolism (PE), clinical decision rules are combined with D-dimer testing to rule out PE, avoiding the need for imaging in those at low risk. Despite sex differences in several aspects of the disease, including its diagnosis, these algorithms are used indiscriminately in women and men. Objectives To compare the performance, defined as efficiency and failure rate, of three pre-imaging diagnostic algorithms for PE between women and men: the Wells rule with fixed or with age-adjusted D-dimer cut-off, and a recently validated algorithm (YEARS). A secondary aim was to determine the sex-specific prevalence of PE. Methods Individual patient data were obtained from six studies using the Wells rule (fixed D-dimer, n = 5; age adjusted, n = 1) and from one study using the YEARS algorithm. All studies prospectively enrolled consecutive patients with suspected PE. Main outcomes were efficiency (proportion of patients in which the algorithm ruled out PE without imaging) and failure rate (proportion of patients with PE not detected by the algorithm). Outcomes were estimated using (multilevel) logistic regression models. Results The main outcomes showed no sex differences in any of the separate algorithms. With all three, the prevalence of PE was lower in women (OR, 0.66, 0.68 and 0.74). In women, estrogen use, adjusted for age, was associated with lower efficiency and higher prevalence and D-dimer levels. Conclusions The investigated pre-imaging diagnostic algorithms for patients suspected of PE show no sex differences in performance. Male sex and estrogen use are both associated with a higher probability of having the disease.

Fibrin clot structure - pro-fibrinolytic effect of oral contraceptives in apparently healthy women

Fibrin metabolism is influenced by many factors. The velocity of fibrin formation, genetic polymorphisms, fibrinolytic features and the structure of the fibrin clot are determinants of fibrin turnover. Oral contraceptives (OCs) have significant impact on the haemostatic system, by increasing the concentration of coagulation factors, plasminogen and tissue plasminogen activator activity, and decreasing the concentration of haemostatic inhibitors. The present study addresses the influence of OCs on fibrin structure and fibrin metabolism. The study included 70 women treated with seven different OC-formulations. Blood was collected at baseline and after six months of OCs. The plasma concentration of fibrinogen, thrombin-antithrombin complex (TAT), plasminogen, plasmin-antiplasmin complex (PAP), D-Dimer and thrombin generation measures were determined. Fibrin structure measures and fibrin clot lysis not affected by the plasma concentration of plasminogen activators and inhibitors were determined. OCs increased the concentration of fibrinogen, TAT, plasminogen, PAP and D-dimer significantly and affected measures of thrombin generation (p<0.001). The maximal optical density of fibrin (p<0.001), the fibrin fibre density (p=0.03), fibrin fibre diameter (p=0.003), fibrin mass-length ratio (p<0.001) and lysis per hour (p<0.001) increased significantly upon OC-treatment. Lysis per hour was not correlated to the concentration of plasminogen. We conclude that the effect of OCs on the coagulation system is balanced by alterations in fibrin structure, facilitating clot lysis and contributing to the fibrinolytic susceptibility already present in women treated with OC. These alterations may counterbalance the OC-induced increased thrombin generation and reduced coagulation inhibitory potential, contributing to maintenance of the haemostatic balance in women receiving OCs.

Endogenous thrombin potential changes during the first cycle of oral contraceptive use

OBJECTIVES

Venous thromboembolism (VTE) risk increases within months of combination oral contraceptive (COC) initiation. Because elevated endogenous thrombin potential (ETP) has been found in several studies to be a VTE risk factor, we evaluated the extent of ETP changes during the initial cycle of an ethinyl estradiol (EE) and levonorgestrel (LNG) COC. We also assessed the relationship between ETP changes and systemic EE and LNG concentrations.

STUDY DESIGN

Participants provided multiple blood samples during a first 21-day cycle of a 30-mcg EE/150-mcg LNG COC and after a further 7 days without an active COC. Thrombin generation measured with and without addition of activated protein C (APC) yielded ETP+APC and ETP-APC and the normalized APC sensitivity ratio (nAPCsr). EE and LNG pharmacokinetic analyses were conducted over 24 h after the first COC tablet and again at steady state.

RESULTS

Thrombin generation was determined in 16 of the 17 women who completed the study. Mean ETP-APC increased steadily to 21% above baseline at 24 h after the 6th COC tablet (COC624; p<.001) and to 28% above baseline at steady state (COC21; p<.001). The percentage increase in mean ETP+APC was considerably more - 54% at COC624 and 79% at steady state. Mean nAPCsr increased by 28% at COC624 and by 41% at steady state. Higher concentrations of EE or LNG were not correlated with greater increases in ETP.

CONCLUSIONS

ETP increases during the first COC cycle were substantial.

IMPLICATIONS

The early increases in ETP may provide biological support for the rapid increase in VTE risk during initial COC use. The lack of association between this clotting system perturbation and the systemic EE concentration is surprising and deserves further study.

Clotting factor changes during the first cycle of oral contraceptive use

OBJECTIVES

The risk of venous thromboembolism (VTE) is highest during the initial months of oral contraceptive (OC) use. We sought to evaluate the extent of hemostatic variable changes during the initial OC cycle and if such changes are related to systemic ethinyl estradiol (EE2) exposure.

STUDY DESIGN

Participants provided multiple blood samples during a 21-day OC cycle (30mcg EE2; 150mcg levonorgestrel) and after a single dose following a washout period. Analytes included D-dimer, factor VIII activity, protein C total antigen and the hepatic proteins corticosteroid-binding globulin (CBG) and sex-hormone-binding globulin (SHBG). EE2 pharmacokinetic analyses related to the 24h after the first OC tablet (OC1) and at steady state (OC21).

RESULTS

Seventeen women completed the study. D-dimer more than doubled by OC6 (p=.013) and remained elevated at OC21 (p=.012). D-dimer levels within women varied widely from day to day. Factor VIII increased 27% by OC2 (p<.001) but declined to a 9% increase by OC21. Protein C increased only 6%. EE2 steady-state area-under-the-curve ranged from 488 to 1103pg∙h/mL; higher levels were not correlated with greater increases in clotting variables. CBG and SHBG increased significantly but were not significantly correlated with levels of EE2 or with the hemostatic variables.

CONCLUSIONS

D-dimer increases during the first OC cycle were at least as great as increases seen with longer OC use. These results provide support for the increased VTE risk during initial OC use. The extreme variability in D-dimer levels may be an important component of this risk.

IMPLICATIONS

This study showed that increases in D-dimer are clearly evident in the first cycle of OC use and may be larger than are seen after a longer duration of use and thus provide biological support for the increased VTE risk during initial OC use found in epidemiological studies.

An update on new orally administered contraceptives for women

INTRODUCTION

The focus in contraception is shifting from oral contraceptives to more effective methods, such as implants and intrauterine devices. Generics are favored by third-party payors. As a result, potentially exciting developments in branded pills to increase safety or to reduce side effects may have gone unnoticed.

AREAS COVERED

This article reviews the features of each of the four new oral contraceptives that have been introduced in the United States and/or Europe in the last few years. The motivation for the development of each product is outlined as is its efficacy, safety, tolerability and the noncontraceptive applications that have been explored are described.

EXPERT OPINION

The hypothesis that using estradiol in place of ethinyl estradiol would reduce the risk of venous thromboembolism is still to be proven. However, the stronger progestogens used in these formulations may offer other tangible benefits for selected women. The new products for extended cycle pill use may have less impact. The flexible regimen can be adopted using any pill, but the approved product does provide convenience to patients. Cost will continue to be the determining factor in the acceptance of these new products, unless substantial health benefits can be conclusively proven.

Increased thrombin generation in women with polycystic ovary syndrome: A pilot study on the effect of metformin and oral contraceptives

OBJECTIVE

Polycystic ovary syndrome (PCOS) is associated with risk factors for cardiovascular disease (CVD) which may be modified by the use of metformin and oral contraceptives (OC). Thrombin generation (TG) measures are risk markers of CVD and address the composite of multiple factors that influence blood coagulation. This prospective, randomized, intervention study evaluated the potential influence of PCOS on TG measures and the effect of OC and/or metformin on TG measures in women with PCOS.

MATERIAL AND METHODS

Ninety patients with PCOS and 35 controls were included. Patients were randomized to 12 months of treatment with metformin, metformin+OC or OC alone. C-reactive protein (CRP), fibrinogen, total cholesterol, trunk fat mass, body mass index, estradiol, testosterone, sex hormone binding globulin (SHBG) as well as TG measures, i.e. the lag time for formation of thrombin, the endogenous thrombin potential (ETP), peak thrombin concentration (peak) and time to peak were determined at baseline and after 12 months of treatment.

RESULTS

CRP and total testosterone were significantly higher and SHBG significantly lower in PCOS women than in controls (P=0.012, P<0.001 and P=0.008, respectively). The TG measures ETP, peak and lag time were increased in women with PCOS compared to controls (P<0.01). Significant correlations were observed between TG measures and fibrinogen, CRP, SHBG and fat trunk mass (P>0.01). ETP (P=0.006), peak (P=0.003) and lag time (P=0.023) remained increased after adjustment for these potential confounders. Treatment with OC and metformin+OC further increased ETP (P<0.001) and peak (P<0.005) and reduced time to peak (P<0.04). The increase in ETP was significantly lower in the metformin+OC group than in the OC group (P<0.05). Metformin alone did not affect TG significantly.

CONCLUSIONS

PCOS is associated with increase in TG measures independent of other risk factors of CVD. OC increase TG measures further and may thus add to the increased risk of CVD already present in women with PCOS.

Does the Progestogen Used in Combined Hormonal Contraception Affect Venous Thrombosis Risk?

Combined hormonal contraceptives (CHCs) use a combination of estrogen and progestogen to provide contraception. The most important risk of using CHCs is venous thromboembolism (VTE). It is unclear whether the type of progestogen used in a method augments that risk. Although the evidence supporting an increase in thrombosis risk is not conclusive, neither is the evidence supporting the benefit of newer progestogens in terms of tolerability or continuation. The benefits of CHCs outweigh the risks and the absolute risk of VTE remains small. A balanced discussion of potential risks and benefits of particular CHC formulations is warranted during contraception counseling.

Epidemiology of hormonal contraceptives-related venous thromboembolism

For many years, it has been well documented that combined hormonal contraceptives increase the risk of venous thromboembolism (VTE). The third-generation pill use (desogestrel or gestodene (GSD)) is associated with an increased VTE risk as compared with second-generation (levonorgestrel) pill use. Other progestins such as drospirenone or cyproterone acetate combined with ethinyl-estradiol (EE) have been investigated. Most studies have reported a significant increased VTE risk among users of these combined oral contraceptives (COCs) when compared with users of second-generation pills. Non-oral combined hormonal contraception, such as the transdermal patch and the vaginal ring, is also available. Current data support that these routes of administration are more thrombogenic than second-generation pills. These results are consistent with the biological evidence of coagulation activation. Overall, the estrogenic potency of each hormonal contraceptive depending on both EE doses and progestin molecule explains the level of thrombotic risk. Some studies have shown a similar increased VTE risk among users of COCs containing norgestimate (NGM) as compared with users of second-generation pill. However, for this combination, biological data, based on quantitative assessment of sex hormone-binding globulin or haemostasis parameters, are not in agreement with these epidemiological results. Similarly, the VTE risk associated with low doses of EE and GSD is not biologically plausible. In conclusion, newer generation formulations of hormonal contraceptives as well as non-oral hormonal contraceptives seem to be more thrombogenic than second-generation hormonal contraceptives. Further studies are needed to conclude on the combinations containing NGM or low doses of EE associated with GSD.

Impact of hormone-associated resistance to activated protein C on the thrombotic potential of oral contraceptives: a prospective observational study

Introduction

The increased thrombotic risk of oral contraceptives (OC) has been attributed to various alterations of the hemostatic system, including acquired resistance to activated protein C (APC). To evaluate to what extent OC-associated APC resistance induces a prothrombotic state we monitored plasma levels of thrombin and molecular markers specific for thrombin formation in women starting OC use. Elevated plasma levels of thrombin have been reported to characterize situations of high thrombotic risk such as trauma-induced hypercoagulability, but have not yet been studied during OC use.

Patients and Methods

Blood samples were collected prospectively from healthy women (n = 21) before and during three menstruation cycles after start of OC. APC resistance was evaluated using a thrombin generation-based assay. Plasma levels of thrombin and APC were directly measured using highly sensitive oligonucleotide-based enzyme capture assay (OECA) technology. Thrombin generation markers and other hemostasis parameters were measured additionally.

Results

All women developed APC resistance as indicated by an increased APC sensitivity ratio compared with baseline after start of OC (p = 0.0003). Simultaneously, plasma levels of thrombin, prothrombin fragment 1+2, and of thrombin-antithrombin complexes did not change, ruling out increased thrombin formation. APC plasma levels were also not influenced by OC use, giving further evidence that increased thrombin formation did not occur.

Conclusions

In the majority of OC users no enhanced thrombin formation occurs despite the development of APC resistance. It cannot be ruled out, however, that thrombin formation might occur to a greater extent in the presence of additional risk factors. If this were the case, endogenous thrombin levels might be a potential biomarker candidate to identify women at high thrombotic risk during OC treatment. Large-scale studies are required to assess the value of plasma levels of thrombin as predictors of OC-associated thrombotic risk.

Multinational, multicentre, randomised, open-label study evaluating the impact of a 91-day extended regimen combined oral contraceptive, compared with two 28-day traditional combined oral contraceptives, on haemostatic parameters in healthy women

OBJECTIVES

To evaluate the impact of a 91-day extended regimen combined oral contraceptive (150 μg levonorgestrel [LNG]/30 μg ethinylestradiol [EE] for 84 days, followed by 10 μg EE for seven days [Treatment 1]) compared with two traditional 21/7 regimens (21 days 150 μg LNG/30 μg EE [Treatment 2] or 150 μg desogestrel [DSG]/30 μg EE [Treatment 3], both with seven days' hormone free), on several coagulation factors and thrombin formation markers.

METHODS

Randomised, open-label, parallel-group comparative study involving healthy women (18-40 years). The primary endpoint was change from baseline in prothrombin fragment 1 + 2 (F1 + 2) levels over six months.

RESULTS

A total of 187 subjects were included in the primary analysis. In all groups, mean F1 + 2 values were elevated after six months of treatment. Changes were comparable between Treatments 1 and 2 (least squares mean change: 170 pmol/L and 158 pmol/L, respectively) but noticeably larger after Treatment 3 (least squares mean change: 592 pmol/L). The haemostatic effects of Treatment 1 were comparable to those of Treatment 2 and noninferior to those of Treatment 3 (lower limit of 95% confidence interval [- 18.3 pmol/L] > - 130 pmol/L).

CONCLUSIONS

The LNG/EE regimens had similar effects on F1 + 2. Noninferiority was demonstrated between extended regimen LNG/EE and DSG/EE.

The effect of different hormonal contraceptives on plasma levels of free protein S and free TFPI

Use of combined oral contraceptives is associated with a three- to six-fold increased risk of venous thrombosis. Hormonal contraceptives induce acquired resistance to activated protein C (APC), which predicts the risk of venous thrombosis. The biological basis of the acquired APC resistance is unknown. Free protein S (PS) and free tissue factor pathway inhibitor (TFPI) are the two main determinants of APC. Our objective was to assess the effect of both hormonal and non-hormonal contraceptives with different routes of administration on free TFPI and free PS levels. We conducted an observational study in 243 users of different contraceptives and measured APC sensitivity ratios (nAPCsr), free TFPI and free PS levels. Users of contraceptives with the highest risk of venous thrombosis as reported in recent literature, had the lowest free TFPI and free PS levels, and vice versa, women who used contraceptives with the lowest risk of venous thrombosis had the highest free TFPI and free PS levels. An association was observed between levels of free TFPI and nAPCsr, and between free PS and nAPCsr. The effect of oral contraceptives on TFPI and PS is a possible explanation for the increased risk of venous thrombosis associated with oral contraceptives.

Increased impact of a contraceptive vaginal ring with ethinyl estradiol and nestorone on C-reactive protein

OBJECTIVE & STUDY DESIGN: In a parallel design, 23 and 22 healthy pre-menopausal women were randomly administered a contraceptive vaginal ring (CVR) delivering 150/15 μg Nestorone®/ethinyl estradiol (EE) daily or an oral contraceptive (OC) containing levonorgestrel and EE (150/30 μg) for three cycles, to compare the effects on C-reactive protein and other markers of inflammation. ANCOVA was performed with baseline values as covariate.

RESULTS

The CVR caused [estimate of difference (95% CI), 109% (16-275%)] higher levels of CRP than the OC, while no difference was observed for leukocyte 1% (-13/+17%) and monocyte counts 6% (-9/+23%). The greater increase in CRP was confined to CVR recipients exhibiting low pre-treatment CRP-levels, whereas no difference was observed in the increases for recipients in the highest tertile of pre-treatment CRP levels.

CONCLUSION

The difference in CRP rise in CVR and OC users does not correspond with the effects on other markers of inflammation and is most likely due to a specific difference in the effect of ethinyl-estradiol combined with nestorone in cases with low CRP.

Comparison of the impact of four generations of progestins on hemostatic variables

This study was undertaken to evaluate the impact of progestins as part of low-estrogen (ethinyl estradiol [EE2] ≤35 μg) combined oral contraceptives (COCs) on hemostatic variables. One hundred ninety-five healthy women took oral contraceptives with following formulations: 35 EE2/norgestimate (NGM), 35 EE2/cyproterone acetate, 35 EE2/norethisterone, 30 EE2/levonorgestrel, 30 EE2/drospirenone (DRSP), 20 EE2/gestodene, and 20 EE2/DRSP, for 6 months. Hemostatic assays (prothrombin time, activated partial thromboplastin time, fibrinogen, resistance to activated protein C ratio, protein C, protein S, factor VIII [FVIII], antithrombin, plasminogen, α2-antiplasmin, inhibitor of plasminogen activator type 1 [PAI-1] and d-dimers) were performed in 3 time points: at baseline, after 3, and 6 cycles. For each formulation, results were compared according to baseline values, intergroup analysis, and the amount of estrogen or progestin component. Most of the variables were changed except FVIII. Significant difference between oral contraceptives was found in antithrombin, protein C, protein S activities, and PAI-1 values, but changes were mostly within reference range.

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.

Introduction to haemostasis from a pharmacodynamic perspective

Biochemical characterization of the haemostatic system has advanced significantly in the past decades. Sub-systems, such as coagulation, fibrinolysis, blood cells and platelets and the vessel wall have been studied by specialists, mostly separately and independently. The time has come to integrate the approaches, and, in particular, to develop tests to document the state of the whole system and to have available adequate pharmacodynamic tests to evaluate treatments. Many examples are available to show that traditional general methods of clotting and lysis do not provide the information that is desired. The present tendency is to use specific methods for specific factors or effects which are very limited in pharmacological information. There is also increasing awareness of the occurrence of rather broad interindividual variability in the haemostatic system. This suggests that individually tailored treatments are required. This is the more relevant since haemostasis is a balance and treatment should be positioned between efficacy and safety. The conclusion is reached that there is a need for integrated or global methods or sets of methods that reflect the complexity and individual status appropriately and allow the practitioner to judge the effects of interventions and their individual aspects.

Effects of a monophasic combined oral contraceptive containing nomegestrol acetate and 17β-oestradiol compared with one containing levonorgestrel and ethinylestradiol on haemostasis, lipids and carbohydrate metabolism

OBJECTIVES

To compare the effects of a combined oral contraceptive (COC) containing nomegestrol acetate and 17β-oestradiol (NOMAC/E2) on haemostasis, lipids, carbohydrate metabolism, C-reactive protein (CRP) and sex hormone-binding globulin (SHBG) with those of a COC containing levonorgestrel and ethinylestradiol (LNG/EE).

METHODS

In a randomised, open-label study, 121 healthy women, 18-50 years of age, were randomly assigned to receive NOMAC/E2 (2.5 mg/1.5 mg) in a 24/4-day regimen (n=60) or LNG/EE (150 μg/30 μg) in a 21/7-day regimen (n=61) for six cycles. The primary outcome was the change from baseline to cycle 6 for all indices.

RESULTS

All parameters were similar at baseline between the two groups. Over six cycles, NOMAC/E2 had less effect on most haemostatic indices than LNG/EE. Lipids were essentially unchanged with NOMAC/E2, whereas with LNG/EE high-density lipoprotein cholesterol decreased and low-density lipoprotein cholesterol and triglycerides slightly increased. NOMAC/E2 induced negligible changes in glucose and insulin parameters, in contrast to LNG/EE. A much smaller increase in CRP was observed with NOMAC/E2 than with LNG/EE. NOMAC/E2 was associated with a greater increase in SHBG.

CONCLUSIONS

The monophasic COC NOMAC/E2 had less influence on haemostasis, lipids and carbohydrate metabolism than the COC LNG/EE.

Direct chromogenic substrate immuno-capture activity assay for testing of factor VII-activating protease

BACKGROUND

The Marburg I (MRI) single nucleotide polymorphism (SNP) of the factor VII-activating protease (FSAP) gene has been associated with thrombophilia and atherosclerotic disease. PCR is used to detect the SNP. Also, the specific FSAP activity to cleave single-chain urokinase-type plasminogen activator (scu-PA) serves as a surrogate for PCR testing. Development of further assays is indicated in order to increase testing opportunities for future studies.

METHODS

A direct chromogenic substrate immuno-capture activity assay for FSAP (FSAP dcs activity assay) was established. Performance characteristics of the FSAP dcs activity assay were compared to the FSAP scu-PA activity assay.

RESULTS

The FSAP dcs activity assay detects FSAP activity from 25% to 150% of the norm. Total CVs ranged from 6% to 10% for FSAP wild type samples and 9%-18% for MRI samples. Correlation between the FSAP dcs and scu-PA activity assays was low (R=0.7). The FSAP dcs activity determined the presence of the MRI FSAP alloenzyme with a diagnostic sensitivity and specificity of 100% [95% confidence interval (CI): 89.6%-100%] and 96.2% (95% CI: 93.2%-97.4%), respectively, whereas the specific FSAP dcs activity increased specificity to 99.0% (95% CI: 97.2%-99.6%).

CONCLUSIONS

The specific FSAP dcs activity represents a reliable method for the detection of the FSAP MRI alloenzyme. Due to the limited correlation between the FSAP dcs and scu-PA activity assays, these different measurands may exhibit different utility in research and clinical applications. Thus, the FSAP dcs activity assay can represent a valuable complement or alternative for FSAP testing in future studies.

Mechanisms of estrogen-induced venous thromboembolism

The use of oral contraceptives (OC) is a well established risk factor for venous thrombosis. It has been known for many years that almost all haemostatic parameters i.e. plasma levels of coagulation factors, anticoagulant proteins and proteins involved in the fibrinolytic pathway change during OC use. The discovery of several risk factors of venous thrombosis in the 1990s shed new light on the association between the effects of OC on the haemostatic system and the increased risk of venous thrombosis. In this review, we summarize the current knowledge on the effects of different kinds of hormonal contraceptives (OC, transdermal contraceptives, vaginal ring and levonorgestrel-releasing intrauterine device) on haemostatic variables and the relationship between the changes of these variables and the risk of venous thrombosis.

Effect of oral contraceptives and ovarian cycle on platelet function

In past decades, numerous epidemiological and clinical studies in women taking oral contraceptives revealed the impact of sex steroids on coagulation factors and the incidence of venous thrombosis. To date, only scarce data regarding the impact of oral contraceptives on platelet function are available. The aim of this study was to further elucidate the impact of sex steroids on platelet function. We conducted an observational study in young women using different types and dosages of monophasic oral contraceptives (OCs) compared to women not taking OCs. During the follicular phase, the mean closure time (CT) in Col/Epi was 168.0 +/- 64.9 s compared to 131.5 +/- 28.9 s during the luteal phase (p=0.012). In Col/Epi cartridges, no difference was detected between women taking second/third generation OCs and low-dose OCs (145.2 +/- 44.3 vs. 169.4 +/- 63.5, p=0.34). In contrast, mean Col/Epi values of women using anti-androgen-containing OCs were less (110.3 +/- 15.6 s) than in both other OC groups (p=0.03 for both comparisons). The same holds for Col/Epi values from women during the follicular- and luteal phases compared to women using anti-androgen-containing OCs (p=0.0002, p=0.013). Significant correlations between progesterone and platelet function in women not using OCs (p=0.02) could be found. In conclusion, the results of the study show that platelet function might be modulated by OCs and the female cycle. As for OCs, the main factor seems to be the progestagen. During the female cycle, the main impact on platelet function might be mediated by progesterone.

20 microg versus >20 microg estrogen combined oral contraceptives for contraception

BACKGROUND

Concern about estrogen-related adverse effects has led to progressive reductions in the estrogen dose in combination oral contraceptives (COCs). However, reducing the amount of estrogen to improve safety could result in decreased contraceptive effectiveness and unacceptable changes in bleeding patterns.

OBJECTIVES

To test the hypothesis that COCs containing </=20 microg ethinyl estradiol (EE) perform similarly as those containing >20 microg in terms of contraceptive effectiveness, bleeding patterns, discontinuation, and side effects.

SEARCH STRATEGY

We searched computerized databases (CENTRAL, MEDLINE, EMBASE, and POPLINE) up to January 2008, and searched the references of eligible trials. We wrote to oral contraceptive manufacturers to identify eligible trials.

SELECTION CRITERIA

English-language reports of randomized controlled trials were eligible that compare a COC containing </=20 microg EE with a COC containing >20 microg EE. We excluded studies where the interventions were designed to be administered for less than three consecutive cycles or to be used primarily as treatment for non-contraceptive conditions. Trials had to report on contraceptive effectiveness, bleeding patterns, trial discontinuation due to bleeding-related reasons or other side effects, or side effects to be included in the review.

DATA COLLECTION AND ANALYSIS

The primary reviewer evaluated all titles and abstracts located in the literature searches to determine whether they met the inclusion criteria. Two reviewers independently extracted data from the studies identified for inclusion. We wrote to the authors when clarifications or additional data were needed. Data were entered and analyzed with RevMan 4.2.

MAIN RESULTS

No differences were found in contraceptive effectiveness for the 13 COC pairs for which this outcome was reported. Compared to the higher-estrogen pills, several COCs containing 20 microg EE resulted in higher rates of early trial discontinuation (overall and due to adverse events such as irregular bleeding) as well as increased risk of bleeding disturbances (both amenorrhea or infrequent bleeding and irregular, prolonged, frequent bleeding, or breakthrough bleeding or spotting).

AUTHORS' CONCLUSIONS

While COCs containing 20 microg EE may be theoretically safer, this review did not focus on the rare events required to assess this hypothesis. Data from existing randomized controlled trials are inadequate to detect possible differences in contraceptive effectiveness. Low-dose estrogen COCs resulted in higher rates of bleeding pattern disruptions. However, most trials compared COCs containing different progestin types, and changes in bleeding patterns could be related to progestin type as well as estrogen dose. Higher follow-up rates are essential for meaningful interpretation of results.

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.