Effects of monophasic low-dose oral contraceptives on fibrin formation and resolution in young women

Low-dose oral contraceptives in adolescents: how low can you go?

CONTEXT

The use of combined oral contraception (COC) before the accrual of peak bone mass in adolescents is common. Despite the tendency to prescribe lower ethinyl estradiol concentrations so as to reduce thromboembolic complications, concerns have developed as to whether low-dose COC provides sufficient estrogen supplementation for adequate adolescent bone development.

OBJECTIVE

This paper reviews the available literature on bone mineral density (BMD) and low-dose COC in adolescents in an effort to determine whether adult-oriented recommendations for the lowest tolerated estrogen dose should apply to adolescent populations.

DESIGN

A MEDLINE search of all English-language literature (1966 to January 2008) was performed using the terms "adolescent," "oral contraception," and "BMD." Bibliographies were reviewed to extract additional relevant sources. Articles were selected based on pertinence to BMD changes in association with low-dose (20 microg ethinyl estradiol) hormonal contraception with emphasis on adolescent study groups.

RESULTS

A limited number of studies examining 20-microg preparations in adolescents have demonstrated a significantly smaller mean percentage BMD acquisition in COC groups vs untreated controls. Bone mineral density decreases appeared to positively correlate with early gynecological age of first COC use and treatment duration.

CONCLUSIONS

Loss of bone mass as a result of hormonal contraceptive use may have serious long-term implications in the adolescent population, who have yet to achieve peak bone density. Both age at first COC use and cumulative estrogen dose appear to be important factors in determining skeletal development in adolescents. Further studies are warranted to inform specific prescribing practices for this population.

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.

Fibrinolytic response to exercise in women using third-generation oral contraceptives

The use of oral contraceptives (OC) is associated with an increased risk of thrombosis, suggesting OC exert procoagulant and/or antifibrinolytic effects. Given that physical exercise physiologically leads to an activation of blood coagulation and fibrinolysis, this study tested the hypothesis that OC might compromise the fibrinolytic response to exercise. Fibrinolytic variables were measured in 10 women (24 +/- 2 years) using OC (a formulation containing 30 micro g ethinylestradiol and 150 micro g desogestrel) and in 11 women without OC (mean +/- SD, 27 +/- 3 years) before, during and after a 1-h run on a treadmill at a velocity corresponding to an oxygen demand of 75-80% of maximum (anaerobic threshold). Exercise testing gave rise to considerable increases of tissue-type plasminogen activator antigen by seven-fold to eight-fold in women taking and not taking OC alike. In the presence of unchanged plasma levels of plasminogen activator inhibitor-1, exercise-induced release of tissue-type plasminogen activator led to enhanced plasmin formation with respect to plasmin-antiplasmin complexes, rising by (mean +/- standard error) 701 +/- 77 ng/ml (P < 0.001) in women using OC and by 695 +/- 117 ng/ml (P < 0.001 versus baseline; NS versus OC users) in controls. The fibrinolytic response to intensive physical exercise is preserved in women using OC and is similar to women not using OC.

Effect of a combined oral contraceptive containing 20 microg ethinyl estradiol and 75 microg gestodene on hemostatic parameters

The effects of a combined oral contraceptive (COC) containing 20 microg ethinyl estradiol (EE) and 75 microg gestodene (GSD) on prothrombin activity (PA), activated partial thromboplastin time (APTT), thrombin time (TT), platelet number, fibrinogen, antithrombin III (ATIII), protein C, protein S and D-dimer were evaluated over 6 months in 23 young, healthy women. Laboratory assessments were performed prior to initiation of COC use (pretreatment) and after 3 and 6 months of use. Results showed no significant changes in fibrinogen, protein C, ATIII or D-dimer during COC use, compared with pretreatment values. The increase in platelet count, decreases in protein S level, PA and APTT, and the prolongation of TT were significant. In conclusion, the use of a COC containing 20 microg EE and 75 microg GSD did not cause any significant changes in the hemostatic parameters studied that could be suggestive of a higher prothrombotic risk. Further studies with a larger sample size are necessary in order to obtain conclusive data.

20 mcg versus >20 mcg 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 also could result in decreased contraceptive effectiveness and unacceptable changes in bleeding patterns.

OBJECTIVES

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

SEARCH STRATEGY

We searched computerized databases (CENTRAL, MEDLINE, EMBASE, and POPLINE) from their inception to November 2003, searched the references of eligible trials, and wrote to oral contraceptive manufacturers to identify eligible trials.

SELECTION CRITERIA

English-language reports of randomized controlled trials that compare a COC containing </=20 mcg EE with a COC containing >20 mcg EE were eligible. 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 11 COC pairs for which this outcome was reported. Several COCs containing 20 mcg 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/infrequent bleeding and irregular, prolonged, frequent bleeding, or breakthrough bleeding or spotting) than their higher-estrogen comparison pills.

AUTHORS' CONCLUSIONS

While COCs containing 20 mcg EE may be theoretically safer, this review did not focus on the rare events required to assess this hypothesis. Data from 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.

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.

The effects of seven monophasic oral contraceptive regimens on hemostatic variables: conclusions from a large randomized multicenter study

We investigated the effects of ethinylestradiol dose (50, 30 and 20 microg) and progestogen type [desogestrel (DSG), gestodene (GSD), levonorgestrel (LNG) and norgestimate (NGM)] in oral contraceptives on 24 hemostatic variables. In a multicenter, randomized, comparative study, 707 healthy, nonsmoking, nulliparous women were treated for six cycles with one of the seven monophasic oral contraceptives tested. Significantly greater increases in prothrombin fragment 1+2 and factor VII (activity and antigen), were found in the DSG, NGM and GSD groups compared to the LNG group. Similarly, significantly lower levels of protein S (free and total) and increased APC-sr (endogenous thrombin potential based) were found in the same groups compared with the LNG group. In addition, the estradiol dose (50 vs. 30 microg) significantly influenced these parameters. All changes were within the normal range and have not been associated with an increased risk of venous thromboembolic event (VTE). However, raised levels of these variables are associated with prothrombotic states such as pregnancy. The significance of the haemostatic changes found in this study in relation to VTE risk remains to be determined, but results of this study probably cannot explain the differences in risk of VTE between OCs containing different progestogens.

Mean transit times and the sites of synthesis and catabolism of tissue plasminogen activator and plasminogen activator inhibitor type 1 in young subjects

Using an invasive technique, we studied the mean transit time, the net quantitative turnover rate, and the sites of synthesis and catabolism of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) in healthy young volunteers in the fasting, steady state. Blood was sampled simultaneously from a large hepatic vein, an artery and the inferior caval vein, while measuring the splanchnic plasma flow rate and the plasma volume. We found that the catabolism of active t-PA and t-PA antigen took place in the splanchnic circulation with net rates of 7.2 and 6.3 pmol/min, respectively. The extraction fraction and the mean transit time in the splanchnic circulation were, respectively, 0.63 and 5.6 min for active t-PA and 0.17 and 21 min for t-PA antigen. Active PAI-1 was synthesized in the splanchnic circulation at a rate of 890 IU/min and had a mean transit time of about 9.8 min. No net extraction of PAI-1 antigen took place in the splanchnic circulation. In conclusion, we demonstrated that active t-PA and t-PA antigen are catabolized and active PAI-1 produced in the splanchnic circulation in young healthy subjects during steady state. Furthermore, our data show that active t-PA was also eliminated outside the splanchnic region with a catabolism rate of about 8.4 pmol/min. No net complex formation could be demonstrated in the peripheral circulation. We therefore suggest that active t-PA is eliminated by a re-uptake in the endothelium in the peripheral vessels or in the lung circulation.

A 12-month clinical investigation with a 24-day regimen containing 15 microg ethinylestradiol plus 60 microg gestodene with respect to hemostasis and cycle control

The effects of a 24-day regimen containing 15 microg ethinyl estradiol (EE) plus 60 microg gestodene on cycle control and on hemostasis, were evaluated in 58 healthy women (age 19-47 years). All women received the pill for 12 months. Withdrawal bleeding at every cycle during the tablet-free interval was experienced by 84.5% of the women. The overall incidence of irregular bleedings was 19.3%. Hemostasis was evaluated in 20 women. No changes in plasma fibrinogen concentrations, nor in prothrombin fragment F1+2 were observed. A slight increase in thrombin-antithrombin III complexes was observed after 6 and 12 months of oral contraceptive use. Antithrombin III activity significantly increased after one-year of pill intake. The concentrations of tissue plasminogen activator and plasminogen activator inhibitor, both antigen and activity, did not change. These results show that very low doses of EE, such as 15 microg, do not impair hemostasis in healthy females. However, the reduction for the EE dose is responsible of some of the effects on cycle control.

Metabolic and fibrinolytic response to changed insulin sensitivity in users of oral contraceptives

The fundamental role of insulin resistance for metabolic changes linked to cardiovascular disease and type 2 diabetes is increasingly recognized. Oral contraceptives (OC) may affect insulin sensitivity, and a detailed characterization hereof, as well as the secondary effects on related metabolic systems, are relevant in the evaluation of the risk of developing vascular disorders or diabetes in OC users. We studied insulin sensitivity index (S(I)), glucose effectiveness (S(g)), and insulin response in young, healthy women by frequently sampled intravenous glucose tolerance tests before and after randomization to 6 months of treatment with ethinyl estradiol in triphasic combination with norgestimate (n = 17) or gestodene (n = 20). Measurements of fasting triglycerides and antigen concentrations of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) were also included. Both compounds increased fasting plasma insulin and reduced S(i) but did not affect S(g). The relationships between S(i) and insulin response were unchanged. No consistent correlation between insulin sensitivity and triglycerides, t-PA, or PAI-1 were demonstrated before or during treatment. We conclude that the treatments were followed by a compensated decrease in insulin sensitivity that was unrelated to changes in triglycerides, t-PA, or PAI-1 antigen.

Hemostatic responses to maximal exercise in oral contraceptive users

OBJECTIVE

This study examined the effect of exercise on markers of fibrinolysis and coagulation in users and nonusers of oral contraceptives.

STUDY DESIGN

Fourteen oral contraceptive users and 14 nonusers performed a maximal exercise test on a cycle ergometer. Blood samples were collected before and immediately after the completion of the test. A repeated-measures analysis of variance was used for statistical analysis with values considered significant at P =.05.

RESULTS

Acute maximal exercise resulted in significant increases in tissue plasminogen activator activity in both groups. There was a trend toward a smaller increase in tissue plasminogen activator activity in oral contraceptive users, but the difference between groups was not statistically significant. Plasminogen activator inhibitor 1 activity was reduced with exercise in both groups but with a significantly greater decrease observed in the nonusers (P <.0001). Prothrombin fragment 1+2 was significantly higher (P <.0001) in the oral contraceptive group but did not change with exercise. Epinephrine levels before and after exercise were similar between the 2 groups, but postexercise norepinephrine concentrations were significantly lower (P =.026) in the oral contraceptive users.

CONCLUSION

These data suggest that oral contraceptive use blunts the fibrinolytic response to exercise. This, together with increased coagulation activation in oral contraceptive users, may alter the hemostatic balance during exercise.

Increased Clearance Explains Lower Plasma Levels of Tissue-Type Plasminogen Activator by Estradiol: Evidence for Potently Enhanced Mannose Receptor Expression in Mice

Several clinical studies have demonstrated an inverse relationship between circulating levels of estrogen and tissue-type plasminogen activator (t-PA). The present study was designed to test the hypothesis that estrogens lower plasma levels of t-PA by increasing its clearance from the bloodstream. 17-Ethinyl estradiol (EE) treatment resulted in a significant increase in the clearance rate of recombinant human t-PA in mice (0.46 mL/min in treated mice v 0.32 mL/min in controls; P < .01). The clearance of endogenous, bradykinin-released t-PA in rats was also significantly increased after EE treatment (area under the curve [AUC], 24.9 ng/mL · min in treated animals v 31.9 ng/mL · min in controls; P < .05). Two distinct t-PA clearance systems exist in vivo: the low-density lipoprotein receptor-related protein (LRP) on liver parenchymal cells and the mannose receptor on mainly liver endothelial cells. Inhibition of LRP by intravenous injection of receptor-associated protein (RAP) as a recombinant fusion protein with Salmonella japonicum glutathione S-transferase (GST) significantly retarded t-PA clearance in control mice (from 0.41 to 0.25 mL/min; n = 5, P < .001) and EE-treated mice (from 0.66 to 0.35 mL/min; n = 5, P < .005), but did not eliminate the difference in clearance capacity between the 2 experimental groups. Similar results were obtained in mice in which LRP was inhibited via overexpression of the RAP gene in liver by adenoviral gene transduction. In contrast, administration of mannan, a mannose receptor antagonist, resulted in identical clearances (0.22 mL/min in controls and 0.24 mL/min in EE-treated mice). Northern blot analysis showed a 6-fold increase in mannose receptor mRNA expression in the nonparenchymal liver cells of EE-treated mice, whereas the parenchymal LRP mRNA levels remained unchanged. These findings were confirmed at the protein level by ligand blotting and Western blotting analysis. Our results demonstrate that EE treatment results in increased plasma clearance rate of t-PA via induction of the mannose receptor and could explain for the inverse relationship between estrogen status and plasma t-PA concentrations as observed in humans.

Increased Clearance Explains Lower Plasma Levels of Tissue-Type Plasminogen Activator by Estradiol: Evidence for Potently Enhanced Mannose Receptor Expression in Mice

Several clinical studies have demonstrated an inverse relationship between circulating levels of estrogen and tissue-type plasminogen activator (t-PA). The present study was designed to test the hypothesis that estrogens lower plasma levels of t-PA by increasing its clearance from the bloodstream. 17-Ethinyl estradiol (EE) treatment resulted in a significant increase in the clearance rate of recombinant human t-PA in mice (0.46 mL/min in treated mice v 0.32 mL/min in controls; P &lt; .01). The clearance of endogenous, bradykinin-released t-PA in rats was also significantly increased after EE treatment (area under the curve [AUC], 24.9 ng/mL · min in treated animals v 31.9 ng/mL · min in controls; P &lt; .05). Two distinct t-PA clearance systems exist in vivo: the low-density lipoprotein receptor-related protein (LRP) on liver parenchymal cells and the mannose receptor on mainly liver endothelial cells. Inhibition of LRP by intravenous injection of receptor-associated protein (RAP) as a recombinant fusion protein with Salmonella japonicum glutathione S-transferase (GST) significantly retarded t-PA clearance in control mice (from 0.41 to 0.25 mL/min; n = 5, P &lt; .001) and EE-treated mice (from 0.66 to 0.35 mL/min; n = 5, P &lt; .005), but did not eliminate the difference in clearance capacity between the 2 experimental groups. Similar results were obtained in mice in which LRP was inhibited via overexpression of the RAP gene in liver by adenoviral gene transduction. In contrast, administration of mannan, a mannose receptor antagonist, resulted in identical clearances (0.22 mL/min in controls and 0.24 mL/min in EE-treated mice). Northern blot analysis showed a 6-fold increase in mannose receptor mRNA expression in the nonparenchymal liver cells of EE-treated mice, whereas the parenchymal LRP mRNA levels remained unchanged. These findings were confirmed at the protein level by ligand blotting and Western blotting analysis. Our results demonstrate that EE treatment results in increased plasma clearance rate of t-PA via induction of the mannose receptor and could explain for the inverse relationship between estrogen status and plasma t-PA concentrations as observed in humans.

An open label, randomized study to evaluate the effects of seven monophasic oral contraceptive regimens on hemostatic variables. Outline of the protocol. Oral Contraceptive and Hemostasis Study Group

Complementary to the epidemiological knowledge on the association between oral contraceptive use and the occurrence of venous thromboembolism, a study was designed to obtain more conclusive data regarding the effect of estrogen dose and progestogen type of oral contraceptives on risk markers for the occurrence of venous thromboembolism. The protocol for this multicenter, randomized, open label, parallel group, comparative study is outlined in the present article. A total of 730 healthy, nonsmoking, mulliparous women were treated for six cycles with one of the seven monophasic oral contraceptives tested in this study. The effects of progestogen type (desogestrel, gestodene, levonorgestrel, and norgestimate) and the effects of ethinyl estradiol dose (50, 30, and 20 micrograms) on various hemostatic variables was assessed, including the key components of the anticoagulant and fibrinolytic system, as well as the coagulation system. The primary outcome variables in the study were prothrombin fragment 1 + 2 and D-dimer.

Effects on hemostasis after two-year use of low dose combined oral contraceptives with gestodene or levonorgestrel

We studied 67 healthy women who were randomly allocated to receive third generation gestodene (Gynera) or second generation levonorgestrel (Microgynon 30) combination of low-dose estrogen oral contraceptives (OCs) for their hemostatic effects over 2 years. Hemostatic changes were apparent within 3 months of OC use. Hematocrit (Hct) was not affected, but hemoglobin (Hb) concentration decreased by 18 months. Shortened prothrombin time (PT) and activated plasma thromboplastin time (APTT) were associated with elevated fibrinogen within the 12-month use of both OCs. Factor VII was reduced only in Micro 30 during the 18 months of use. Enhanced thrombin-antithrombin (TAT)-complex level was seen at 18 months of Gynera use. Prothrombin fragment1+2 (F1+2) rise was seen at 3 months with Micro 30. Reduced antithrombin III (ATIII) activity was seen at 18 months with Gynera and at 24 months with Micro 30. Increased protein C activity was seen at 3 months and reduced protein S occurred at 18 months of Gynera use. Tissue plasminogen activator (t-PA) activity was enhanced for 6 months in both OCs with raised D-dimer levels for 12 months with Gynera and 6 months with Micro 30. Decreased t-PA antigen was seen at 18 months and decreased urokinaselike plasminogen activator (u-PA) antigen occurred throughout the 24 months of both OCs use. Enhanced u-PA activity was only seen in Gynera users. Elevated plasminogen levels were apparent throughout both OCs use. PAI-1 levels were significantly decreased with Micro 30. With Gynera, the decreased PAI-1 activity was seen only at 18 months and PAI-1 antigen at 12 months. No change in platelets and von Willebrand factor (vWF) were seen in long-term OC use except that beta-thromboglobulin (beta-TG) showed decreased trends reaching statistical significance by 18 and 24 months of Micro 30 use and by 24 months of Gynera use. A further significant decrease in beta-TG, u-PA antigen, ATIII, and protein S levels were seen 3 months after pill stoppage compared with pretreatment levels. Activated protein C resistance (APCR) was negative in all subjects before and during OC use. The study indicated dynamic balance between coagulation and fibrinolysis with no endothelial activation. However, because some hemostatic markers showed wide fluctuations during OC use, a longer term study is warranted to investigate any adverse hemostatic changes that might enhance the risks of venous thromboembolism in Asian subjects known to be less prone to thrombosis.

Haemostatic changes and the oral contraceptive pill

Oral contraceptives have been linked to an increased incidence of thrombovascular disease. This may be mediated by their effects on the haemostatic system. An increase in the activity of coagulation Factors VII, X and fibrinogen occur with pill usage. Increased Factor VII levels are dependent on both the oestrogen and progestogen component of the oral contraceptive. A reduction in antithrombin III levels has also been observed in some but not all studies. Increased fibrinolysis has also been shown in oral contraceptive users which should balance the changes in the coagulation pathway. The increase in fibrinolytic potential is thought to be due to a decrease in the levels of plasminogen activator inhibitor I combined with an increase in the levels of plasminogen; tissue plasminogen activator antigen is decreased in most studies. The increased levels of endpoints of coagulation and fibrinolysis in pill users indicate that enhanced activity of both systems is occurring in vivo. The increased coagulation activity appears to be balanced by the rise in fibrinolytic activity, so preserving haemostatic balance. Enhanced platelet activity has also been shown in women taking oral contraceptives. Thrombus formation can result, however, when local vascular wall damage exists, or when other risk factors for thrombo-embolism, such as older age and smoking, coexist and create a local activation resulting in a thrombus. In these situations, the small differences in levels of coagulation factors in women taking different oral contraceptive formulations may be important. Pills containing the lowest doses of oestrogen (20 micrograms ethinyloestradiol) have shown the least changes in haemostatic factors. The progestogen component of the pill modifies the effect of oestrogen on the haemostatic system.

No influence of proinsulin and insulin on plasma levels of plasminogen activator inhibitor type 1 and tissue plasminogen activator in young women before and during intake of contraceptive steroids

Clinical observations in patients predisposed to cardiovascular disorders and recent experimental observations suggest that proinsulin and insulin participate in the regulation of fibrinolysis in vivo. In the present study, we examined if proinsulin and insulin affect the constitutive (fasting) secretion of plasminogen activator inhibitor type 1 (PAI-1) and tissue plasminogen activator (t-PA) in young healthy women (N = 17). We also measured the antigen concentrations of PAI-1 and t-PA during slow and fast changes in proinsulin and insulin levels induced by oral (OGTT) and intravenous (IVGTT) glucose tolerance tests. The assessments were performed before and after 6 months of treatment with contraceptive steroids, which have a well-defined influence on the fibrinolytic variables. We observed no consistent correlations between fasting values of proinsulin, insulin, PAI-1, and t-PA either before or during hormonal treatment. Before hormonal treatment, PAI-1 and t-PA antigen levels decreased (P < .05) during the hyperproinsulinemia and hyperinsulinemia induced by the OGTT and IVGTT. After hormonal intake for 6 months, a decrease only in t-PA concentrations during the OGTT was observed despite similar proinsulin and insulin responses to the glucose loads. Our findings suggest that proinsulin and insulin have no influence on the regulation of plasma levels of PAI-1 and t-PA in young healthy women, irrespective of intake of contraceptive steroids.

The effect of oestrogen dose and progestogen type on haemostatic changes in women taking low dose oral contraceptives

OBJECTIVE

To determine the effect of oestrogen dose and progestogen type on the coagulation and fibrinolytic systems of a group of normal healthy women taking three different oral contraceptive combinations.

DESIGN

Plasma levels of factor VII, X, antithrombin III, protein C, fibrinogen, tissue plasminogen activator activity, plasminogen activator inhibitor I antigen and fibrin (D-dimer) degradation products were measured at pretreatment, 6, 14, 22 weeks of treatment and at 6 weeks post-treatment in a group of 67 women taking either 30 micrograms ethinyloestradiol/150 micrograms desogestrel (n = 21), 20 micrograms ethinyloestradiol/150 micrograms desogestrel (n = 24), 30 micrograms ethinyloestradiol/75 micrograms gestodene (n = 22).

PARTICIPANTS

Sixty-seven healthy normal women, 18 to 34 years, smoking fewer than 15 cigarettes per day. The subjects were within 10% of their normal body weight and had no history of thromboembolic disease.

SETTING

Coombe Women's Hospital and St James's Hospital, Dublin, Ireland.

RESULTS

Factor VII and X levels were significantly raised on treatment with both the 30 micrograms ethinyloestradiol/desogestrel and gestodene combinations. Higher levels of factor VII activity were observed in the 30 micrograms ethinyloestradiol/desogestrel combination compared with the gestodene combination. Factor VII and X were not significantly affected by the 20 micrograms ethinyloestradiol combination. Increased plasminogen, fibrinogen and D-dimer levels and decreased plasminogen activator inhibitor I antigen levels were observed during the treatment phases in all three groups. Antithrombin III and protein C activity did not change during treatment with any of the oral contraceptives studied.

CONCLUSIONS

Low dose oral contraceptives cause an activation of the coagulation system which is balanced by an activation of the fibrinolytic system. Reducing the dose of ethinyloestradiol from 30 micrograms to 20 micrograms reduces the effect on factor VII and X. This effect can be modified by the progestogen. The lesser effect of the 20 micrograms combination may make this a safer option for some women than pills containing a higher dose of oestrogen.

The role of thromboxane A2 in increased whole blood platelet aggregation in oral contraceptive users

Epidemiological studies have shown that oral contraceptives increase the risk of thromboembolic disease in susceptible women however the mechanisms involved are unclear. We investigated whole blood platelet aggregation in 44 women randomly allocated to 6 cycles of treatment with either gestodene (75ug) or desogestrel (150ug) combined with 30ug ethinyloestradiol (EE). The in vitro effects of aspirin and a thromboxane synthetase inhibitor, dazmegrel (UK38485) were also investigated. Oral contraceptive treatment caused a significant increase in collagen, arachidonic acid (AA) and ADP induced whole blood platelet aggregation. PAF induced aggregation was unchanged. There were no significant differences in the levels of platelet aggregation between the desogestrel/30ugEE and gestodene/30ugEE groups. In vitro incubation of platelets with aspirin and dazmegrel prevented the oral contraceptive induced increase in platelet aggregation. Dazmegrel caused an on treatment decrease in PAF induced aggregation in the desogestrel/30ugEE but not the gestodene/30ugEE group. The results of this study indicate that the use of oral contraceptives is associated with an increase in platelet aggregation that is mediated by changes in thromboxane/prostacyclin ratio(TXA2/PGI2). Although no significant differences were found between the two different progestogen combinations, the effects of dazmegrel on PAF induced aggregation suggest a possible difference in the progestogen modifying effects of desogestrel and gestodene which is unmasked when thromboxane synthetase is inhibited.

The effects of two phasic oral contraceptives on hemostasis and platelet function

OBJECTIVE

To compare the effects on hemostatic parameters of a combiphasic oral contraceptive containing desogestrel and ethinyl estradiol (DSG/EE) and a triphasic oral contraceptive containing levonorgestrel and ethinyl estradiol (LNG/EE).

METHODS

In an open-label, randomized, group-comparative study in 10 healthy volunteers per treatment group, the effects on parameters of coagulation, anticoagulation, fibrinolysis, antifibrinolysis and platelet function were determined at baseline, after three treatment cycles, and after a post-treatment cycle. Changes from baseline were analyzed using a paired t-test, whereas between-group differences were analyzed by means of an analysis of co-variance.

RESULTS

Both OC preparations induced modest changes of some coagulation, anticoagulation, fibrinolysis and antifibrinolysis parameters, although all mean values remained within the normal range. No significant effects were observed with either OC with respect to platelet function. Statistically significant differences between the two preparations could occasionally e observed: the concentrations of antithrombin II (AT-III) and Factor VII were higher with the DSG/EE preparation than with LNG/EE preparation at the end of treatment and AT-III activity, AT-III concentration, Factor X concentration, and plasminogen activity were higher with DSG/EE than with LNG/EE in the post-treatment cycle.

CONCLUSIONS

Combiphasic DSG/EE and triphasic LNG/EE, both OCs with a comparable amount of EE per cycle, had no clinically significant effect on the overall hemostatic balance.

Assessment of endothelial function during oral contraception in women with insulin-dependent diabetes mellitus

The effects of contraceptive steroids on the expression of endothelial homeostasis were examined by direct and indirect measures in women with insulin-dependent diabetes mellitus (IDDM) in a prospective nonrandomized controlled study. Study subjects were 13 women with uncomplicated IDDM treated with a monophasic combination of 30 micrograms ethinyl estradiol and 75 micrograms gestodene for 12 consecutive cycles and 13 women of comparable diabetic status as control. During the study period, none of the participants developed increased renal albumin excretion, which was used as a direct measure of endothelial function. In the indirect assessment of endothelial function, we found a proportionate increase in plasma levels of thrombin-antithrombin III (TAT) complexes and D-dimer during treatment. Hormonal intake was followed by decreased antigen concentrations of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (type 1 [PAI-1]), whereas the activities of t-PA and PAI-1 were unchanged. Plasma levels of plasminogen and histidine-rich glycoprotein (HRG) increased and decreased, respectively, whereas an increase in von Willebrand factor was observed in the treatment group. No significant changes in direct or indirect measures were observed in the control group during the observation period of 12 months. In conclusion, no adverse effect on endothelial function was demonstrated by direct measures, but our findings suggest that a procoagulant state, compensated by enhanced activity of the fibrinolytic system, is induced by hormonal treatment. Clinical and metabolic monitoring is recommended if the use of oral contraceptives in women with IDDM is extended.

Multicenter study in Hungary with a 30 micrograms ethinylestradiol- and 150 micrograms desogestrel-containing monophasic oral contraceptive

Among the countries in Central and Eastern Europe, Hungary has a high oral contraceptive prevalence rate. Until recently, however, Hungarian women have not had access to combined oral contraceptives with new, third-generation progestogens. Marvelon (30 micrograms ethinylestradiol and 150 micrograms desogestrel) was first introduced in 1981 in Western Europe and has, in a number of different studies, proven an effective and well-tolerated oral contraceptive with no effect on blood pressure and a favorable lipid profile. Marvelon was introduced in Hungary in October 1991. Prior to its introduction, a multicenter study was undertaken in Hungary with Marvelon to confirm the clinical results of studies from other countries. The present study confirmed Marvelon to be an effective, well-tolerated combined oral contraceptive with no relevant effect on blood pressure. Remarkable improvements were noted, especially with regard to side-effects, in switchers from other oral contraceptives. It is concluded that Marvelon is a valuable extension of the range of contraceptive methods available in Hungary.

Effects of contraceptive steroids on cardiovascular risk factors in women with insulin-dependent diabetes mellitus

OBJECTIVE

We evaluated established cardiovascular risk factors within lipoprotein metabolism, hemostasis, and endothelial function in women with insulin-dependent diabetes mellitus who were using oral contraceptives.

STUDY DESIGN

Twenty-five women with uncomplicated insulin-dependent diabetes mellitus, allocated to treatment with a monophasic combination of 30 micrograms ethinyl estradiol and 75 micrograms gestodene (treatment group, n = 12) or with nonhormonal contraception (control group, n = 13), were prospectively followed up for 12 months. Nonparametric methods were used for statistical evaluation.

RESULTS

No statistical differences in the biochemical risk markers were noted between the two groups at the start of the study. In the treatment group serum levels of low-density lipoprotein cholesterol decreased, whereas the concentrations of total cholesterol, high-density lipoprotein cholesterol, very-low-density lipoprotein cholesterol, and triglycerides were unchanged. Within the coagulation system factor VII coagulant activity increased, while fibrinogen levels were unchanged. In the fibrinolytic system we found unchanged activities but decreased antigen concentrations of tissue plasminogen activator and plasminogen activator inhibitor. The concentration of von Willebrand factor increased, but no change in albumin excretion rates were found. In the control group no changes in any of the variables were observed.

CONCLUSION

Intake of modern oral contraceptives does not deteriorate the cardiovascular risk profile in women with insulin-dependent diabetes mellitus, but our study indicates a risk of disturbances of the endothelial integrity, which needs further investigation.

Hemostasis profile and lipid metabolism with long-interval use of a desogestrel-containing oral contraceptive

Thirty healthy women, aged 18 to 37, were randomly allocated to treatment with a desogestrel-containing oral contraceptive, with 20 women using a nine-week on, one-week off regimen, and 10 women using the traditional regimen. At 0, 3 and 12 months, blood samples were drawn for liver proteins, lipoproteins and hemostatic variables. No significant changes were observed between the two regimens. Sex hormone binding globulin (SHBG) and corticosteroid binding globulin (CBG, transcortin) were increased two- to four-fold, as a measure of estrogenicity. Minimal changes occurred within the lipoprotein cholesterol fractions, whereas there were some increases within the lipoprotein triglyceride fractions. Among the hemostatic variables, there were significant increases of fibrinogen, factor VII and thrombin/antithrombin III (TAT) complex. The coagulation inhibitors, antithrombin III, protein C and protein S, were essentially unchanged. A decrease of both tissue plasminogen activator antigen (t-PA) and tissue plasminogen activator inhibitor activity (PAI activity) of the fibrinolytic system was observed. A nine-week regimen does not seem to alter lipid metabolism and coagulation more than a three-week regimen.

Coagulation and anticoagulation effects of contraceptive steroids

Epidemiologic data support the notion that first-generation high-dose oral contraceptives (containing > 80 micrograms of estrogen) increased the incidence of thromboembolic events. The quantitative interpretation of these data is difficult because results were often confounded by life-style factors and inadequate diagnostic procedures. With the introduction of modern low-dose combination oral contraceptives, the incidence of thromboembolic events decreased markedly. Although all combined oral contraceptives induce statistically significant changes in hemostatic factors, these changes are generally within normal ranges, and their clinical significance is questionable. Overall, increased activity in hemostatic mechanisms appears to remain in balance. Progestin-only formulations seem to affect hemostatic parameters to a much lesser degree, and their use has not led to an increased risk of thrombosis. Interindividual variations in pharmacokinetics and pharmacodynamics of contraceptive steroids are great and could tentatively explain why certain persons may be at an increased risk of thrombosis. Although most studies have looked at steady-state conditions during contraceptive steroid intake, it would seem prudent to investigate further the hemostatic system during a non-steady-state condition, such as that occurring during the first few days of the pill-free interval.

Fibrinolytic parameters in women undergoing ovulation induction

OBJECTIVE

The purpose of this study was to evaluate the effect of elevated levels of circulating estradiol on the clotting and fibrinolytic system in patients undergoing controlled ovarian hyperstimulation.

STUDY DESIGN

Fifty-two patients undergoing controlled ovarian hyperstimulation with human menopausal gonadotropins or urofollotropin were asked to participate. Blood for hemostasis parameters was obtained on the days that patients returned for estradiol sampling. Sample days were identified as cycle days 1 to 5 (baseline), 6 to 9, and 10 to 14. Each factor was analyzed by repeated-measures analysis of variance and correlation analysis.

RESULTS

A significant decline was observed for tissue plasminogen activator antigen and plasminogen activator inhibitor type 1 activity from baseline to cycle days 10 to 14. As serum estradiol levels increased throughout each phase (maximum mean estradiol 739.8 pg/ml), a significant linear decrease was observed for both tissue plasminogen activator antigen and plasminogen activator inhibitor type 1 activity, whereas thrombin-antithrombin III complexes did not change significantly. A significant positive correlation was also observed for plasminogen activator inhibitor activity and tissue plasminogen activator antigen level over all cycle days examined.

CONCLUSION

Down-regulation of the fibrinolytic system was observed as estradiol levels increased. However, thrombin formation did not change, thus suggesting that elevated circulating estradiol alone does not predispose to a thromboembolic event.

A comparative metabolic study of two low-estrogen-dose oral contraceptives containing desogestrel or gestodene progestins

OBJECTIVES

Our objective was to compare the effects of low-estrogen-dose oral contraceptives containing desogestrel or gestodene progestins on metabolic risk markers for coronary heart disease.

STUDY DESIGN

A cross-sectional comparison of 70 women who used a formulation that contained 30 micrograms ethinyl estradiol and 150 micrograms desogestrel, 43 women who used a formulation that contained 30 micrograms ethinyl estradiol and 75 micrograms gestodene, and 54 women who did not use steroidal contraceptives was performed.

RESULTS

Oral contraceptive users had higher concentrations of high-density lipoproteins than did women in the control group (+10% to +20%, p < 0.001) primarily because of increases in high-density lipoprotein subfraction 3. High-density lipoprotein subfraction 2 concentrations were higher in users of the desogestrel formulation. Low-density lipoprotein cholesterol concentrations were normal in oral contraceptive users, but triglyceride concentrations were high (+80% to +100%, p < 0.001). Fasting glucose, insulin, and C-peptide concentrations were similar in the three groups, but their responses to a glucose load were higher in oral contraceptive users than in controls (p < 0.01 to p < 0.001). The late plasma insulin response to glucose was higher in the women who used the gestodene formulation than in those who used the desogestrel formulation.

CONCLUSIONS

The metabolic profiles induced by these oral contraceptives were remarkably similar and may reflect the activity of the estrogen component.