EFFECT OF A PROGESTIN-ESTROGEN ORAL CONTRACEPTIVE ON BLOOD CLOTTING FACTORS

Are all estrogens created equal? A review of oral vs. transdermal therapy

BACKGROUND

To compare oral and transdermal delivery systems in domains of lipid effects; cardiovascular, inflammatory, and thrombotic effects; effect on insulin-like growth factor, insulin resistance, and metabolic syndrome; sexual effects; metabolic effects including weight; and effects on target organs bone, breast, and uterus.

METHODS

Review of the literature 1990-2010. Studies selected on basis of applicability, quality of data, and relationship to topic.

RESULTS

Data applicable to the comparisons of oral versus transdermal delivery systems for postmenopausal estrogen therapy were utilized to perform a review and formulate conclusions.

CONCLUSIONS

Significant differences appear to exist between oral and transdermal estrogens in terms of hormonal bioavailability and metabolism, with implications for clinical efficacy, potential side effects, and risk profile of different hormone therapy options, but neither results nor study designs are uniform. Bypassing hepatic metabolism appears to result in more stable serum estradiol levels without supraphysiologic concentrations in the liver. By avoiding first-pass metabolism, transdermal hormone therapy may have less pronounced effects on hepatic protein synthesis, such as inflammatory markers, markers of coagulation and fibrinolysis, and steroid binding proteins, while oral hormone therapy has more pronounced hyper-coagulant effects and increases synthesis of C-reactive protein and fibrinolytic markers. Both oral and transdermal delivery systems have beneficial effects on high-density lipoprotein cholesterol to low-density lipoprotein cholesterol ratios (oral>transdermal), while the transdermal system has more favorable effects on triglycerides. Incidence of metabolic syndrome and weight gain appears to be slightly lower with a transdermal delivery system. Oral estrogen's significant increase in hepatic sex hormone binding globulin production lowers testosterone availability compared with transdermal delivery, with clinically relevant effects on sexual vigor.

Elevated hemostatic factor levels as potential risk factors for thrombosis

OBJECTIVES

To review the state of the art relating to elevated hemostatic factor levels as a potential risk factor for thrombosis, as reflected by the medical literature and the consensus opinion of recognized experts in the field, and to make recommendations for the use of specific measurements of hemostatic factor levels in the assessment of thrombotic risk in individual patients.

DATA SOURCES

Review of the medical literature, primarily from the last 10 years.

DATA EXTRACTION AND SYNTHESIS

After an initial assessment of the literature, key points were identified. Experts were assigned to do an in-depth review of the literature and to prepare a summary of their findings and recommendations. A draft manuscript was prepared and circulated to every participant in the College of American Pathologists Conference XXXVI: Diagnostic Issues in Thrombophilia prior to the conference. Each of the key points and associated recommendations was then presented for discussion at the conference. Recommendations were accepted if a consensus of the 27 experts attending the conference was reached. The results of the discussion were used to revise the manuscript into its final form.

CONCLUSIONS

Consensus was reached on 8 recommendations concerning the use of hemostatic factor levels in the assessment of thrombotic risk in individual patients. Detailed discussion of the rationale for each of these recommendations is presented in the article. This is an evolving area of research. While routine use of factor level measurements is not recommended, improvements in assay methodology and further clinical studies may change these recommendations in the future.

Effect of sex hormones on hypoprothrombinemia induced by N-methyltetrazolethiol in rats

N-Methyltetrazolethiol (NMTT) increased prothrombin time (PT) and decreased plasma factor VII and prothrombin levels only in vitamin K-deficient male rats. In female rats identical treatment with NMTT did not produce hypoprothrombinemia. Conventional and germ-free rats displayed no significant difference in the manifestation of hypoprothrombinemia, but the increase of PT in NMTT-treated vitamin K-deficient rats was greater in the germ-free males. Estradiol administration or castration of male rats retarded manifestation of vitamin K deficient syndromes such as increases of PT and activated partial thromboplastin time (APTT), decreases of plasma factor VII and prothrombin levels, and increases of plasma and liver descarboxyprothrombin (PIVKA) levels, and testosterone injection to the castrated rats restored these changes. In female rats testosterone treatment or castration enhanced the manifestation of hypoprothrombinemia and estradiol treatment to the castrated females retarded it. Gamma-glutamyl-carboxylase activity was increased by vitamin K-deficiency but not inhibited by testosterone or NMTT. These data suggest that estrogen protects the rat against manifestation of hypoprothrombinemia even with NMTT treatment, while androgen enhances vitamin K deficiency, and supplementation of vitamin K prevents its deficiency in NMTT-treated rats.

Haemostatic changes in tall girls treated with high doses of ethinyloestradiol

Haemostasis was studied in 8 tall girls during treatment with high doses of synthetic oestrogens for a period of 1 to 28 months. The girls received 0.5 mg ethinyloestradiol daily from day 1 to day 25 and 15 mg norethisteron daily from day 21 to day 25. All were without clinical signs of thromboembolism. Factors of the prothrobmin complex were significantly elevated in the tall girls compared to healthy controls of the same age. Fibrinogen was also significantly elevated. Factor VIII-related antigen was significantly higher in the tall girls and the ratio between factor VIII activity and factor VIII-related antigen was significantly decreased in the tall girls, as compared to the controls. Thrombin time was significantly shortened. Tests of primary haemostasis showed an increased tendency for thrombocytes to adhere to glass and to aggregate spontaneously and after stimulation with ADP or collagen. Whether these in vitro signs of hypercoagulability indicate an enhanced risk of throbmoembolic complications in tall girls treated with high doses of oestrogens remains to be established. However, these girls should be watched carefully for clinical signs of throbmoembolic complications during treatment.

Oral contraceptives and platelet aggregation

There are conflicting data in the literature concerning the effects of oral contraceptives on platelet aggregation. We studied 26 healthy women who used oral contraceptives for at least three months. The control group consisted of 25 healthy women of childbearing age, who were receiving no medications. No differences in platelet aggregation in response to adenosine diphosphate, epinephrine, and collagen were found between the two groups.

The comparative effects of a synthetic and a 'natural' oestrogen on the haemostatic mechanism in patients with primary amenorrhoea

A synthetic and a natural oestrogen were administered alternately for three months to nine women with primary amenorrhoea using a randomized cross-over schedule. Measurements of haemostatic function were performed before and at the end of each treatment period. No significant change in haemostatic function was observed after treatment with the 'natural' oestrogen, oestriol succinate. In contrast, treatment with a synthetic oestrogen, ethinyloestradiol, caused shortening of the prothrombin time and an increase in plasma concentration of factor VII and plasminogen. These data support other observations in suggesting that natural oestrogens may have fewer potentially adverse effects on haemostatic function than synthetic oestrogen.

The effects of long-term therapy with oestriol succinate on the haemostatic mechanism in postmenopausal women

In a previous report we showed that oestriol succinate administered to postmenopausal women caused fewer changes in haemostatic function over a four-month period than ethinyloestradiol. Potential longer-term effects were studied in postmenopausal women treated for osteoporosis with oestriol succinate for up to 12 months. Over this period there was no significant change in concentration of plasma coagulation factors, an increase in plasminogen concentration and euglobulin lysis activity, and an inconsistent increase in platelet sensitivity to aggregation induced by ADP and collagen. The relative lack of effect of oestriol succinate on coagulation function is encouraging with regard to the future incidence of thromboembolic complications of therapy.

[Blood coagulation and fibrinolysis in women receiving estrogen, gestagen and estrogen-gestagen-contraceptives (author's transl)]

Eight femal subjects received a contraceptive with a low estrogen content (Neogynon), the estrogen component (50 mug ethinylestradiol) and consecutively the gestagen component (250 mug D-Norgestrel) of the contraceptive. Each treatment cycle was followed by a control cycle. At various times of the control and therapy cycles several coagulation and fibrinolytic parameters were investigated. Statistical analyses were performed by multivariate two-factorial analysis of variance. Plasminogen exhibities a statistically significant increase during the treatment with ethinylestradiol and the combination of this steroid with D-norgestrel. No significant changes were found for all other parameters, including partial thromboplastin time, fibriogen, factors X, IX, VIII, factor VIII-related antigen, antithrombin III and fibrin(ogen)degradation products.

Sagittal sinus thrombosis related to oral contraceptives. Case report

✓ A case of thrombosis of the cortical veins and superior sagittal sinus occurred in a young woman with no obvious predisposing factors other than the possible implication of contraceptive pills. Angiographic, surgical, and pathological findings are presented. Survival in this case resulted from a large cranial decompression, and later a ventriculojugular shunt to control extraventricular obstructive hydrocephalus.

Oral contraceptives and gastrointestinal disorders

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Control of conception by hormonal steroids

Experience with the use of progestinestrogen preparations as oral contraceptives indicates that they inhibit fertility by preventing ovulation and that their action is clearly a physiological process. Their efficiency as antifertility agents is extraordinary. An examination of their physiological effects over many years of use indicates that actions to be expected from the hormonal properties of the steroidal components occur but that none of these constitute pathological phenomena. Rather, we observe a state conditioned by the rather constant hormonal milieu resulting from the particular dosages and regimes of use. Thus far, despite use by millions of women, none of the alleged pathological adverse reactions (such as thromboembolism) to the drugs have been established as more than coincidental. Clearly beneficial effects are inherent not only in the avoidance of risks attendant upon pregnancy but also in improvements in menstrual function (regularity, reduction of hypermenorrhea and dysmenorrhea) and perhaps in a prophylactic effect upon certain abnormalities of the reproductive tract (cervical anaplasia, endometrial cystic and adenomatous hyperplasia). Psychogenic phenomena due to use of oral contraceptives are difficult to measure, but beneficial effects would seem to outweigh adverse ones.