Progestogens and cardiovascular reactions associated with oral contraceptives and a comparison of the safety of 50- and 30-microgram oestrogen preparations

Women's health in The BMJ: a data science history

OBJECTIVE

To determine how the representation of women's health has changed in clinical studies over the course of 70 years.

DESIGN

Observational study of 71 866 research articles published between 1948 and 2018 in The BMJ.

MAIN OUTCOME MEASURES

The incidence of women-specific health topics over time. General linear, additive and segmented regression models were used to estimate trends.

RESULTS

Over 70 years, the overall odds that a word in a BMJ research article was 'woman' or 'women' increased by an annual factor of 1.023, but this rate of increase varied by clinical specialty with some showing little or no change. The odds that an article was about some aspect of women-specific health increased much more slowly, by an annual factor of 1.004. The incidence of articles about particular areas of women-specific medicine such as pregnancy did not show a general increase, but rather fluctuated over time. The incidence of articles making any mention of women, gender or sex declined between 1948 and 2005, after which it rose steeply so that by 2018 few papers made no mention of them at all.

CONCLUSIONS

Over time women have become ever more prominent in BMJ research articles. However, the importance of women-specific health topics has waxed and waned as researchers responded ephemerally to medical advances, public health programmes, and sociolegal changes. The appointment of a woman editor-inchief in 2005 may have had a dramatic effect on whether women were mentioned in research articles.

[Hormonal contraception and vascular risk: CNGOF Contraception Guidelines]

Venous thromboembolism and arterial ischemic events are the main deleterious diseases associated with the use of combined hormonal contraceptives (CHC). Even though their composition has been substantially improved, the vascular risk persists with the most recent CHCs use. If the vascular risk associated with CHCs containing 50μg EE is significantly higher than with those containing less than 50μg, there is no evidence that the CHCs containing either 30 or 20μg of EE induce different venous risks. CHC containing gestodene, desogestrel, drospirenone or cyproterone acetate are associated with a higher risk of venous thrombosis compared with levonorgestrel-containing CHCs. CHC containing norgestimate are associated with similar venous thrombosis risk than CHC containing levonorgestrel. Venous thrombosis risk of non-oral routes of administration of CHC appears to be equivalent to the risk of CHC containing gestodene or desogestrel, but this result is based on a small number of epidemiological studies. Before prescribing a CHC, it is important to determine all vascular risk factors. Family history of ischemic arterial event or venous thromboembolism disease should be routinely sought before any CHC prescription. All CHCs are contraindicated in women with biological thrombophilia, in women with combined vascular risk factors, in women with first-degree family history of arterial or venous event (under age 50) as well as in women suffering of migraine with aura. Progestin-only contraceptives are not associated with vascular risk (arterial or venous) outside of medroxyprogesterone acetate. In women with higher vascular risk, progestin-only contraceptives (administered by oral, sous-cutaneous or intra-uterine routes) can be prescribed.

Oral Contraceptives and HRT Risk of Thrombosis

Estrogen-containing medication, prescribed either for contraception in women of reproductive age or for prevention of cardiovascular events and osteoporosis as well as for alleviation of symptoms related to menopause, is associated with changes in the hemostatic balance and contributes to increased risk of development of venous thromboembolic complications. This risk is dose and medication dependent, increases with age, congenital and/or acquired predisposition to thrombosis, and mode of administration. This review attempts to summarize the current knowledge regarding the pathophysiology of oral contraceptive (OC) and hormone replacement therapy (HRT) -induced prothrombotic state in women, the risk of thrombosis associated with administration of various commercially available OCs and HRT, the additional risk in women with hereditary or acquired thrombophilia, and the currently available recommendations regarding massive screening of women for thrombophilia prior to initial prescription or continuation of treatment with OCs and HRT preparations.

Combined oral contraceptives: venous thrombosis

BACKGROUND

Combined oral contraceptive (COC) use has been associated with venous thrombosis (VT) (i.e., deep venous thrombosis and pulmonary embolism). The VT risk has been evaluated for many estrogen doses and progestagen types contained in COC but no comprehensive comparison involving commonly used COC is available.

OBJECTIVES

To provide a comprehensive overview of the risk of venous thrombosis in women using different combined oral contraceptives.

SEARCH METHODS

Electronic databases (Pubmed, Embase, Web of Science, Cochrane, CINAHL, Academic Search Premier and ScienceDirect) were searched in 22 April 2013 for eligible studies, without language restrictions.

SELECTION CRITERIA

We selected studies including healthy women taking COC with VT as outcome.

DATA COLLECTION AND ANALYSIS

The primary outcome of interest was a fatal or non-fatal first event of venous thrombosis with the main focus on deep venous thrombosis or pulmonary embolism. Publications with at least 10 events in total were eligible. The network meta-analysis was performed using an extension of frequentist random effects models for mixed multiple treatment comparisons. Unadjusted relative risks with 95% confidence intervals were reported.Two independent reviewers extracted data from selected studies.

MAIN RESULTS

3110 publications were retrieved through a search strategy; 25 publications reporting on 26 studies were included. Incidence of venous thrombosis in non-users from two included cohorts was 0.19 and 0.37 per 1 000 person years, in line with previously reported incidences of 0,16 per 1 000 person years. Use of combined oral contraceptives increased the risk of venous thrombosis compared with non-use (relative risk 3.5, 95% confidence interval 2.9 to 4.3). The relative risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate, or drospirenone were similar and about 50-80% higher than for combined oral contraceptives with levonorgestrel. A dose related effect of ethinylestradiol was observed for gestodene, desogestrel, and levonorgestrel, with higher doses being associated with higher thrombosis risk.

AUTHORS' CONCLUSIONS

All combined oral contraceptives investigated in this analysis were associated with an increased risk of venous thrombosis. The effect size depended both on the progestogen used and the dose of ethinylestradiol. Risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate and drospirenone were similar, and about 50-80% higher than with levonorgestrel. The combined oral contraceptive with the lowest possible dose of ethinylestradiol and good compliance should be prescribed-that is, 30 μg ethinylestradiol with levonorgestrel.

Oral contraceptives and the periodontium

Oral contraceptives are a safe and effective means of contraception for millions of women worldwide. The first formulations of these drugs contained much higher doses of estrogens and progestins than those available today, and these were associated with an unacceptably high rate of unwanted effects including serious cardiovascular events. In addition, a number of case reports and clinical studies suggested that use of the first generation oral contraceptives was also associated with an increased risk for gingival and/or periodontal disease. Unfortunately, many of these early studies suffered from significant methodological flaws which throw their findings into question. Nonetheless, these studies provided the basis for a perception among the dental profession that oral contraceptives increase the risk for gingivitis and/or periodontitis. Realisation that the adverse events profile of oral contraceptives was dose dependant led to the development of the modern low dose formulations that are in use today. There have been far fewer studies to investigate whether modern oral contraceptives have any impact on the periodontium compared to studies of the early contraceptive formulations, but the quality of the more recent research is undoubtedly better. Following extensive review of the relevant literature and consideration of the historical perspective, the best available evidence strongly supports that oral contraceptives no longer place users at any increased risk for gingivitis or periodontitis. Oral contraceptives should not be viewed as a risk factor for gingival or periodontal disease.

Different combined oral contraceptives and the risk of venous thrombosis: systematic review and network meta-analysis

OBJECTIVE

To provide a comprehensive overview of the risk of venous thrombosis in women using different combined oral contraceptives.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

PubMed, Embase, Web of Science, Cochrane, Cumulative Index to Nursing and Allied Health Literature, Academic Search Premier, and ScienceDirect up to 22 April 2013.

REVIEW METHODS

Observational studies that assessed the effect of combined oral contraceptives on venous thrombosis in healthy women. The primary outcome of interest was a fatal or non-fatal first event of venous thrombosis with the main focus on deep venous thrombosis or pulmonary embolism. Publications with at least 10 events in total were eligible. The network meta-analysis was performed using an extension of frequentist random effects models for mixed multiple treatment comparisons. Unadjusted relative risks with 95% confidence intervals were reported. The requirement for crude numbers did not allow adjustment for potential confounding variables.

RESULTS

3110 publications were retrieved through a search strategy; 25 publications reporting on 26 studies were included. Incidence of venous thrombosis in non-users from two included cohorts was 1.9 and 3.7 per 10,000 woman years, in line with previously reported incidences of 1-6 per 10,000 woman years. Use of combined oral contraceptives increased the risk of venous thrombosis compared with non-use (relative risk 3.5, 95% confidence interval 2.9 to 4.3). The relative risk of venous thrombosis for combined oral contraceptives with 30-35 µg ethinylestradiol and gestodene, desogestrel, cyproterone acetate, or drospirenone were similar and about 50-80% higher than for combined oral contraceptives with levonorgestrel. A dose related effect of ethinylestradiol was observed for gestodene, desogestrel, and levonorgestrel, with higher doses being associated with higher thrombosis risk.

CONCLUSION

All combined oral contraceptives investigated in this analysis were associated with an increased risk of venous thrombosis. The effect size depended both on the progestogen used and the dose of ethinylestradiol.

Hormonal contraceptives and venous thromboembolism: an epidemiological update

Since the early 1960s, it has been well documented that combined hormonal contraceptives increase the risk of cardiovascular disease. Newer generation of oral formulations, as well as non-oral contraceptives (transdermal and vaginal), have been recently studied for thrombotic risk. This review provides a summary of the association between hormonal contraceptives and venous thromboembolism with emphasis on new formulations of hormonal contraceptives as well as route of administration. A systematic search of Medline database was done for all relevant articles which included women having used third generation pills, and the development of new progestins. Eligible articles published in English and reporting the risk of venous thromboembolism (VTE) (pulmonary embolism or deep venous thrombosis) among users of hormonal contraceptives were reviewed. A quantitative assessment was made from included studies. Current use of drospirenone or cyproterone oral combined contraceptives increased the risk of VTE compared with second generation pills (pooled OR: 1.7; 95% confidence interval [95% CI]: 1.4-2.2 and OR: 1.8; 95% CI: 1.4-2.3, respectively). In the context of contraceptive use, non-oral route of ethinyl-estradiol administration seems to be more thrombogenic than oral route. In contrast, low doses of both oral progestin contraceptives and intrauterine levonorgestrel could be safe with respect to VTE risk. In conclusion, newer generation formulations of hormonal contraceptives, as well as the non-oral hormonal contraceptive, seem to be more thrombogenic than second generation hormonal contraceptives.

Hormonal contraception and venous thromboembolism

BACKGROUND

New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published.

AIM

To evaluate new epidemiological data and to propose clinical consequences.

DESIGN

A literature survey.

METHODS

Studies assessing the risk of specific types of hormonal contraception were evaluated, compared and set into a clinical perspective.

RESULTS

The majority of newer studies have demonstrated a threefold increased risk of VTE in current users of medium- and low-dose combined oral contraceptives (COCs) with norethisterone, levonorgestrel (LNG) or norgestimate compared with non-users. The same studies have demonstrated a sixfold increased risk of VTE in users of combined pills with desogestrel, gestodene, drospirenone or cyproteroneacetate, and in users of the contraceptive vaginal ring, compared with non-users. The rate ratio of VTE between users of COCs with newer progestogens compared with users of COCs with LNG was 1.5-2.8 in seven studies and 1.0 in two studies. Progestogen-only contraception did not confer an increased risk of VTE in any study. The incidence rate of VTE in non-pregnant women aged 15-49 years using non-hormonal contraception is three per 10 000 years.

CONCLUSIONS

For women starting on hormonal contraception, we recommend medium- or low-dose combined pills with norethisterone, LNG or norgestimate as first-choice preparations. For the many women who are users of COCs with newer progestogens, although the absolute risk of VTE is low, a change to combined pills with norethisterone, LNG or norgestimate may halve their risk of VTE. Finally, we recommend COCs with 20 μg estrogen combined with the older progestogens to be launched in the Scandinavian countries. Women at an increased risk of VTE should consider progestogen-only contraception or non-hormonal contraception.

Reciprocal coordination of a combination oral contraceptive containing desogestrel+ethinyl estradiol on the expression of LOX-1 and LDLR in placental trophoblast cells

BACKGROUND

The aim of this study was to assess the consistency of antiatherosclerotic potential of a combination oral contraceptive steroid (ethinyl estradiol+desogestrel) by rating its effect on the differential expression of the low-density lipoprotein receptor (LDLR) and lectin-like oxidized LDL (LOX-1) receptor.

STUDY DESIGN

Cells from placental trophoblast cell line (JAR) and differentiated primary placental trophoblast cells isolated from term human placentae were used for this study. Expressions of LOX-1 and LDLR were assessed by immunoblot and immunocytochemistry assays. Differential effects of the constituent steroids in the combination of ethinyl estradiol and desogestrel were verified on the expression profile of the receptors.

RESULTS

Desogestrel opposed the effect of ethinyl estradiol on LOX-1 expression, and when used in combination, the combination oral contraceptive reduced the expression of LOX-1 in contrast to LDLR. The characteristic change in the expressions of LOX-1 and LDLR showed an antiatherosclerotic improvisation at the unique combination of ethinyl estradiol (10 ng/mL) and desogestrel (20 ng/mL).

CONCLUSION

The aforesaid combination of ethinyl estradiol and desogestrel keeps LOX-1 and LDLR reciprocally expressed in antiatherosclerotic mode.

Effect of a combination oral contraceptive (desogestrel+ethinyl estradiol) on the expression of low-density lipoprotein receptor and its transcription factor (SREBP2) in placental trophoblast cells

BACKGROUND

This in vitro study deals with the effect of a combination oral contraceptive steroid - desogestrel and ethinyl estradiol - on the expression of low-density lipoprotein receptor (LDLR) and its transcription factor (SREBP2) in assessing the functional effectiveness of the LDLR.

STUDY DESIGN

Differentiated primary placental trophoblast cells isolated from term human placentae and cells from Jar cell line were used for the study. Low-density lipoprotein receptor and SREBP2 expressions were assessed by immunocytochemistry and immunoblot assays with and without combination contraceptive steroid challenge. Functional activity of LDLR was studied by rating the profile of cellular uptake of fluorescent Dil-LDL (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanin perchlorate-LDL). Quantitation of Dil-LDL was done spectrofluorometrically.

RESULTS

Variation of concentration(s) of either of the components of a combination preparation (desogestrel and ethinyl estradiol) showed a comparable change in the expressions of LDLR and SREBP2 to attain their optimal levels. Maximum expression and a significant functional effectiveness were observed at a unique combination of desogestrel (20 ng/mL) and ethinyl estradiol (10 ng/mL).

CONCLUSION

The stimulatory effect of a combination contraceptive steroid on LDLR expression is an associated phenomenon of the contraceptive-mediated stimulation of SREBP2 expression.

Study of low-density lipoprotein receptor regulation by oral (steroid) contraceptives: desogestrel, levonorgestrel and ethinyl estradiol in JEG-3 cell line and placental tissue

BACKGROUND

The aim of this study was to compare in vitro the role of two oral contraceptives, desogestrel (a less androgenic derivative of levonorgestrel) and levonorgestrel--alone and in combination with ethinyl estradiol--on low-density lipoprotein (LDL) receptor regulation by assessing receptor protein expression and functional effectiveness.

STUDY DESIGN

Placental tissue and cultured placental cells (JEG-3) were used to study the expression and endocytotic activity of LDL receptor protein. The expression of the receptor was assessed by immunocytochemistry and immunoblot assays with and without contraceptive challenge. Functioning activity of LDL receptor was studied by measuring the rate of uptake of LDL by placental cells. Quantification of LDL was based on the total cholesterol content of the lipoprotein.

RESULTS

A combination of desogestrel (20 ng/mL of incubation medium) and ethinyl estradiol (10 ng/mL of incubation medium) maintained the LDL receptor at high level of expression and functioning mode. In contrast, the double-blind preparation of levonorgestrel (20 ng/mL) and ethinyl estradiol (10 ng/mL) had shown much lower expression as well as receptor-mediated LDL uptake. The concentration of contraceptives used in this study was similar to the prevailing concentration of oral contraceptives in clinical use.

CONCLUSION

Higher expression of LDL receptor and enhanced rate of LDL uptake by the receptor protein projects the possibility that there might be less atherosclerosis-related disorders from the combination of desogestrol and ethinyl estradiol.

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.

Oral contraceptives and DDAVP nasal spray: patterns of use in managing vWD-associated menorrhagia: a single-institution study

The purpose of this study was to examine patterns of use for oral contraceptive and desmopressin acetate nasal spray, both used in managing menorrhagia in adolescents with von Willebrand disease (vWD). Hospital records of adolescents with documented vWD and menorrhagia were reviewed retrospectively. Subjects with vWD type 1 (n = 36) administered either oral contraceptives (OC) or intranasal desmopressin acetate (DDAVP) and followed from 6 months to 4 years were selected for inclusion. Treatment outcomes were examined with respect to effectiveness and safety. Assessing menstrual blood loss using PBAC scores from pretreatment and treatment periods determined effectiveness. Safety was evaluated by monitoring reported adverse events. No significant differences were identified in treatment effectiveness for controlling menorrhagia in vWD adolescents in the OC and intranasal DDAVP group comparisons: 86% versus 77% (P > 0.05), respectively. When combining both treatment groups, the majority of vWD adolescents, 81% (P > 0.05), experienced alleviation of menorrhagia symptoms. Treatment failures were attributed to either the inability of a regimen to control bleeding or to adverse events, including severe headaches and flushing with DDAVP. Safety outcomes were not significantly greater in vWD patients with menorrhagia when OC were compared with intranasal DDAVP. Both medical approaches, OC and DDAVP nasal spray, used in managing menorrhagia in adolescents with documented type I vWD were well tolerated and showed equivalent effectiveness, and no serious adverse events were reported.

Venous thromboembolic disease in users of low-estrogen combined estrogen-progestin oral contraceptives

OBJECTIVE

To assess the relationship between venous thromboembolic disease (VTE) and use of low-estrogen dose (<50 microg) combined estrogen-progestin oral contraceptives (OC) and three thrombosis-related gene mutations in a United States population.

DESIGN

This case-control study was conducted in 1998-2000 among women ages 15-44 years who were members of the Kaiser Permanente Medical Care Program [KPMCP] (Northern and Southern California). Cases were women with incident VTE; about three times as many women frequency matched for age were randomly selected as controls from the KPMCP membership in the same years. Data were collected in a 1 h face-to-face interview; blood was drawn to extract DNA to test for gene polymorphisms. The analysis data set comprised 196 cases (mean age 35.3 years) and 746 controls (mean age 36.2 years).

RESULTS

The adjusted odds ratio (OR) for VTE associated with current OC use was 4.07 (95% confidence interval [CI]: 2.77-6.00). The OR associated with OC use was higher for women who were obese than in the nonobese (p = 0.01 for likelihood test for interaction) and in women without predisposing medical conditions (p = 0.02 for interaction). The adjusted OR for VTE was 7.10 (95% CI: 2.33-21.61) in women with factor V Leiden (G1691A) mutation, 2.83 (95% CI: 0.70-11.63) in women with prothrombin G20210A mutation and 0.26 (95% CI: 0.10-0.65) in women with the MTHFR C677T mutation. The OR for VTE in OC users with factor V Leiden mutation (11.32) was elevated more than in OC users without the mutation (3.20) and women with the mutation who were non-OC users (8.42), but confidence intervals overlapped.

CONCLUSIONS

The risk of VTE is increased in users of low-estrogen OC formulations. Obese women appear to be at greater risk of VTE when using OCs.

Lipid profile in women over 35 years old using triphasic combined oral contraceptives

Twenty-nine women aged 35 years old or more, using triphasic combined oral contraceptive (COC) were evaluated during six cycles for the following parameters: total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and its subfraction HDL2, triglycerides, apoproteins A and B, Castelli risk index I and II (cholesterol/HDL-C and LDL-C/HDL-C) and apoprotein ratio (apoprotein B/apoprotein A). The same laboratory measurements were done in a control group of 49 non-COC-user women. The results showed that there were no differences on most of the studied parameters between user and nonuser women. There was a significant reduction of HDL-C and HDL2-C, although within the normal range. In addition, it was observed a significant increment of triglycerides and apoprotein B at 6 months of follow-up only in user group (p < 0.05), although within the normal range. It is concluded that the use of levonorgestrel triphasic COC appeared to have no additional adverse impact when used by women aged over 35 years. Further studies are needed to obtain conclusive data.

Pharmacokinetic differences between Caucasian and Japanese subjects after single and multiple doses of a potential combined oral contraceptive (Org 30659 and EE)

OBJECTIVES

To compare the pharmacokinetic parameters and safety of the progestagen, Org 30659, (17alpha)-17-hydroxy-11-methylene-19-norpregna-4,15-dien-20-yn-3-one), and ethinyl estradiol (EE) in Caucasian and Japanese women after single and multiple doses.

METHODS

This was an open-label parallel design of a single dose followed by a multiple dose period in healthy young Japanese and Caucasian subjects.

RESULTS

The area under the curve (AUC) of Org 30659 after single dosing was increased by a factor of 1.75 [90% confidence interval (CI): 1.48-2.08] in Japanese women compared to Caucasian women. At steady state, this difference increased to a factor of 1.90 (90% CI: 1.60-2.25). The AUC of EE after single dosing was similar in Caucasian and Japanese women, but at steady state it was increased by a factor 1.38 (90% CI: 1.15-1.64) in the Japanese group. Weight normalization reduced, but did not remove, all the observed differences. Sex hormone binding globulin played no significant role in the differences between Caucasian and Japanese subjects. Both the single- and multiple-dose treatments with Org 30659/EE were generally well tolerated by all subjects. The Japanese population reported more and different treatment-related adverse events than the Caucasian population.

CONCLUSIONS

The peak concentration and extent of exposure of Org 30659, and to a lesser extent of EE, in Japanese women are higher than in Caucasian women. Furthermore, the peak concentration and extent of exposure at steady state of Org 30659, and to a lesser extent of EE, are higher than would be predicted assuming linear pharmacokinetics over time. No major safety issues were observed.

Effect of Implanon® and Norplant® subdermal contraceptive implants on serum lipids—a randomized comparative study

The objective of this study was to assess the possible differences in effects of Implanon (etonogestrel 68 mg, single-rod) and Norplant (levonorgestrel 36 mg, six capsules) implants on serum lipids over 2 years of use. In this 2-year open randomized study of 80 implant acceptors, selected serum lipids were tested before implant insertion and at 6, 12 and 24 months after implant insertion. The lipid parameters evaluated were: total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides, apolipoprotein A-I and apolipoprotein B. During the 2 years, the serum lipid pattern in the Implanon users was not significantly different from that of the Norplant users. There was slight decrease in HDL-C levels in both the groups but there were no significant changes in the HDL/TC ratio and the HDL/LDL ratio. Although it was statistically significant, the magnitude of decrease in HDL-C from preinsertion levels in Implanon users was only 5.8% at the end of 2 years.

A 13-month multicenter clinical experience of a low-dose monophasic oral contraceptive containing 20 microg ethinylestradiol and 75 microg gestodene in Latin American women

This prospective, multicenter study was conducted to evaluate the contraceptive reliability, cycle control and tolerability of a 21-day oral contraceptive regimen containing 20 microg ethinylestradiol and 75 microg gestodene in four Latin American countries (Mexico, Argentina, Brazil and Colombia). Participants took trial medication daily for 21 days. Contraceptive efficacy, cycle control and tolerability were evaluated over a period of 13 cycles. Efficacy data gathered from 5,109 treatment cycles were obtained from 393 participants. The trial medication proved to be an effective contraceptive and provided good cycle control. One pregnancy because of poor compliance was recorded. This resulted in a study Pearl index of 0.25. Forty-six percent of Latin American women reported one intracyclic spotting bleeding episode and 37.6% reported one intracyclic breakthrough bleeding (medium/excessive bleeding) episode during cycles 2-4 (primary target). Overall, intracyclic bleeding was reported in 41%. Overall, there was a trend towards a lower incidence of spotting in all the countries and this difference had statistical significance between Argentina and the others three countries (p < 0.05) during cycles 2-4. This trend was also apparent with respect to breakthrough bleeding, but again the difference did not achieve statistical significance. The discontinuation rate because of adverse events was low (3%); no serious adverse events were reported. More than 78% of the women in the four countries maintained constant body weight or lost weight (2 kg) during the study. The treatment effect on blood pressure was negligible. There were no appreciable changes in mean laboratory values over the course of the study.

Using a low-dose contraceptive in women 35 years of age and over: 20 microg estradiol/100 microg levonorgestrel

The efficacy, safety, and cycle control of a low-dose oral contraceptive (OC) containing 20 microg ethinyl estradiol (EE) and 100 microg levonorgestrel (LNG) has been demonstrated in a large trial with 1708 women (>or=15 years old with regular menstrual cycles). The objective of this study was to analyze the same parameters in 218 of the 1708 women who were 35 years of age and older. Women were administered the 28-day, combination OC (20 microg EE/100 microg LNG; 21 days active medication/7 days placebo) for up to 3 years. During 3859 cycles evaluated for efficacy, one pregnancy occurred (Pearl index 0.34). The most common adverse events cited as reasons for discontinuation were hypertension (3% of subjects), headache (2%), and metrorrhagia (2%). One subject withdrew as a result of a serious adverse event. Breakthrough bleeding, spotting, and bleeding and spotting occurred in 2.9%, 11.0%, and 6.8%, respectively, of the 3739 cycles evaluated for cycle control. This low-dose, monophasic regimen of 20 microg EE/100 microg LNG is an effective, safe, and tolerable contraceptive and provides good cycle control for women 35 years of age and older.

The emerging use of the 20-microg oral contraceptive

OBJECTIVE

To highlight studies that investigated the efficacy, safety, and tolerability of low-dose oral contraceptives (OCs) containing 20 microg of ethinyl estradiol (EE) and to discuss the use of these low-dose contraceptives in women from adolescence to menopause and the noncontraceptive health benefits likely to be afforded by low-dose contraceptives.

DESIGN

Relevant literature was identified by searching MEDLINE and EMBASE. Other sources were located by consulting the bibliographies of the material collected from Medline and EMBASE. Sources for additional information included documents from the United States Food and Drug Administration and the Physicians' Desk Reference (54th ed.).

CONCLUSION(S)

The current lowest available dose of EE used for OCs in the United States is 20 microg. Formulations with 20 microg of EE are efficacious and have a low incidence of estrogen-related side effects. Since this lowest effective EE dose inhibits ovarian activity, 20 microg of EE should also provide the noncontraceptive health benefits of OCs. Both contraceptive and noncontraceptive benefits of OCs are available to most women from adolescence to menopause without complications.

Oral contraceptives. Risks

The modern combination oral contraceptive (OC) has become a mainstay in the effort to provide safe, reliable, and effective contraception. Safety concerns with OC use have largely been laid to rest as a result of multiple and extensive studies. Even so, misperceptions about the risks of OC use and a relative lack of recognition concerning the numerous and important noncontraceptive benefits limit their use, thus putting women in needless danger for unintended pregnancy. Indeed, even fears concerning breast cancer risk and OC use have been unsubstantiated by an abundance of data. Clinicians should be aware of the safety of low-dose OCs so that they can provide accurate and individualized counseling concerning the applicability of OCs and other contraceptive methods.

Occlusive vascular diseases in oral contraceptive users. Epidemiology, pathology and mechanisms

Despite being an unprecedented departure from normal physiology, the combined oral contraceptive is not only highly effective, but it also has a remarkably good safety record. Concerns over safety persist, though, particularly with regard to venous thromboembolism (VTE), stroke and myocardial infarction (MI). Epidemiological studies consistently show an increase in risk of VTE, but the results are more contentious with regard to arterial diseases. Despite 40 years of research, the mechanisms behind these adverse effects are not understood. In this review, we integrate information from published studies of the epidemiology and pathology of the occlusive vascular diseases and their risk factors to identify likely explanations for pathogenesis in oral contraceptive users. Oral contraceptives induce both prothrombotic and fibrinolytic changes in haemostatic factors and an imbalance in haemostasis is likely to be important in oral contraceptive-induced VTE. The complexity of the changes involved and the difficulty of ascribing clinical significance has meant that uncertainty persists. A seriously under-researched area concerns vascular changes in oral contraceptive users. Histologically, endothelial and intimal proliferation have been identified in women exposed to high plasma estrogen concentrations and these lesions are associated with thrombotic occlusion. Other structural changes may result in increased vascular permeability, loss of vascular tone and venous stasis. With regard to arterial disease risk, epidemiological information relating to dose effects and joint effects with other risk factors, and studies of pathology and changes in risk factors, suggests that oral contraceptive use per se does not cause arterial disease. It can, nevertheless, synergise very powerfully with subclinical endothelial damage to promote arterial occlusion. Accordingly, the prothrombotic effects of the oral contraceptive estrogen intervene in a cycle of endothelial damage and repair which would otherwise remain clinically silent or would ultimately progress - in, for example, the presence of cigarette smoking or hypertension - to atherosclerosis. Future work in this area should focus on modification of the effects of established risk factors by oral contraceptive use rather than modification of the supposed risk of oral contraceptive use by established risk factors. Attempts to understand vascular occlusion in oral contraceptive users in terms of the general features of VTE or with reference to atherosclerosis may be limiting, and future work needs to acknowledge that such occlusions may have unique features. Unequivocal identification of the mechanisms involved would contribute considerably to the alleviation of fears over vascular disease and to the development of even safer formulations.

Cardiovascular events associated with different combined oral contraceptives: a review of current data

Studies of combined oral contraceptive (COC) use and cardiovascular disease have been conducted against a background of low cardiovascular risk in young women, changing COC composition and changing user selection and monitoring. Studies of myocardial infarction have found inconsistent results, possibly because of differences in the prevalence of risk factors (particularly smoking and raised blood pressure) in the populations studied. In the absence of a history of smoking and other conventional risk factors, current users of modern COCs probably do not have an increased risk of myocardial infarction. Neither are former users at risk. Evidence for important differences in the risk of myocardial infarction between formulations is weak and contradictory. Current users of low estrogen dose COCs have a small increased risk of ischaemic stroke although most of the risk occurs in women with other risk factors (notably smoking, hypertension and probably a history of migraine). Former users of COCs do not have an increased risk of ischaemic stroke. There is insufficient information to determine whether major differences in the risk of ischaemic stroke exist between products. Current users appear to have a modestly elevated risk of haemorrhagic stroke, mainly in women older than 35 years; former users do not. Data examining the risk of haemorrhagic stroke in current COC users with other risk factors are very sparse, as are those relating to the haemorrhagic stroke risk associated with particular COCs. Numerous studies have found, with remarkable consistency, an elevated risk of venous thromboembolism among current users of low estrogen dose COCs. The risk is substantially elevated among women with various inherited clotting factor defects. The effects in COC users with other risk factors for venous thrombosis tend to be less pronounced and more inconsistent. A number of studies have found higher relative risks among current users of low estrogen dose COCs containing desogestrel or gestodene, than among users of similar products containing levonorgestrel. A number of explanations, in terms of bias or confounding, have been proposed for these clinically small differences. At best, empirical evidence for these explanations, is weak. The risk of cardiovascular disease of any description is low in COC users. Women can minimise, and possibly eliminate entirely, their arterial risks by not smoking and by having their blood pressure checked before using a COC (in order to avoid its use if raised blood pressure is discovered). Users may decrease their venous thromboembolic risk by their choice of COC preparation although the effects will be modest.

Multicenter study of the efficacy, cycle control and tolerability of a phasic desogestrel-containing oral contraceptive

OBJECTIVE

To investigate the efficacy, cycle control and tolerability of a phasic oral contraceptive containing ethinylestradiol 35/30/30 microg and desogestrel 50/100/150 microg.

METHODS

A multicenter study was conducted involving 2070 healthy, fertile women, who received study treatment for six treatment cycles.

RESULTS

Most of the participants (79%) had previously been using an alternative oral contraceptive. In 10,408 treatment cycles, two women became pregnant while on treatment (Pearl index, 0.25). The incidence of irregular bleeding was 10% before treatment, rising to 27% at cycle 1, and decreasing to 11% by cycle 6. Irregular bleeding was mainly due to spotting rather than breakthrough bleeding and the incidence of breakthrough bleeding remained below 2.2% for most of the study period. Only 1.8% of women withdrew due to bleeding irregularities. First-time oral contraceptive users initially experienced more irregular bleeding than switchers but these differences lessened over time. The most common adverse events during treatment were headache, breast tenderness and nausea. The incidence of these adverse events fell to below pretreatment levels with continued use.

CONCLUSION

The phasic preparation was effective and well tolerated.

A multicenter randomized comparison of cycle control and laboratory findings with oral contraceptive agents containing 100 microg levonorgestrel with 20 microg ethinyl estradiol or triphasic norethindrone with ethinyl estradiol

OBJECTIVE

This study was undertaken to compare the effects of 2 oral contraceptive regimens on menstrual cycle control and laboratory findings.

METHODS

In a multicenter randomized study 100 microg levonorgestrel with 20 microg ethinyl estradiol (Alesse or Loette) was given to 155 healthy women. A triphasic preparation of 500, 750, and 1000 microg norethindrone with 35 microg ethinyl estradiol (Ortho-Novum 7/7/7 or TriNovum) was given to 167 women for 1 to 4 cycles of treatment.

RESULTS

Overall, the percentages of normal menstrual cycles and the percentages of cycles with intermenstrual and withdrawal bleeding were similar between the 2 treatment groups. In the levonorgestrel with ethinyl estradiol group, there was a statistically significantly longer latent period and a statistically significantly shorter withdrawal bleeding episode. Adverse events were similar between treatment groups, and none were serious. Most mean changes from baseline laboratory values were comparable between groups, although the mean increase in cholesterol concentration was statistically significantly lower in the levonorgestrel with ethinyl estradiol group. Changes in triglyceride and glucose concentrations were not statistically significantly different between groups.

CONCLUSIONS

Levonorgestrel (100 microg) with ethinyl estradiol (20 microg) provides menstrual cycle control equivalent to that obtained with triphasic norethindrone with ethinyl estradiol (75% higher estrogen dose) with similar safety and tolerability.

Women's health

Symptoms reliably attributable to menopause are vasomotor symptoms and vaginal dryness. Other symptoms are not directly related to the menopause. HRT or ERT are effective in providing symptom relief and preventing disease prevalent in postmenopausal women. HRT or ERT is beneficial in women with RA. Little data concerns safety in SLE patients, but there are theoretical advantages to using HRT or ERT in women with SLE and two studies that indicate it is safe. Other forms of treatment are available to women who cannot or will not use HRT or ERT.

Oral contraceptives highlight the genotype-specific association between serum phospholipids and activated factor VII

The present analysis was undertaken to study the effect of oral contraceptive (OC) use on activated factor VII (FVIIa) in subjects characterized by FVII genotypes, with the further aim of evaluating the role of lipids in this pharmacological interaction. In OC users (n=42) and nonusers (n=130) of comparable age, we examined the FVII phenotypic variables (FVII coagulant activity [FVIIc], FVII antigen, and FVIIa), FVII genotypes (the 353R/Q and 5'F7 polymorphisms analyzed in combination; alleles M1/M2 and A1/A2, respectively), and a number of lipid and lipoprotein parameters: serum concentrations of total cholesterol (chol), low density lipoprotein and high density lipoprotein-chol, triglycerides, phospholipids (PhLs), apolipoprotein A1, and lipoprotein(a). PhLs, triglycerides, apolipoprotein A1, chol, FVII antigen, FVIIc, and high density lipoprotein-chol levels were shown to be statistically higher in users than nonusers. FVII levels, particularly those of FVIIa and FVIIc, were much higher in homozygotes for the A1 and M1 alleles (A11 M11), especially in OC users. A strong association was found between PhL and FVIIa: in the multiple regression analysis, women taking OCs who had elevated PhL concentrations also had very high levels of FVIIa, but only if their genotype was A11 M11. These results indicate that the increased FVII levels in OC users depend on the FVII genotype and that high PhL concentrations predict very high levels of FVIIa and FVIIc.

Changes in coagulation factors and fibrinolytic components of postmenopausal women receiving continuous hormone replacement therapy

OBJECTIVE

The effect of hormone replacement therapy (HRT) on coagulation factors and fibrinolytic components in postmenopausal women was studied for 6 months to elucidate whether continuous HRT has an influence on thrombosis.

METHODS

One hundred and thirty-four postmenopausal women were divided into three groups according to treatment: 39 women who had undergone hysterectomy and oophorectomy received 0.625 mg/day of conjugated equine estrogen (CEE) continuously (CEE therapy), 48 postmenopausal women received both 0.625 mg/day of CEE and 2.5 mg/day of medroxyprogesterone acetate (MPA) continuously (CEE/MPA therapy) and 47 postmenopausal women received placebo as control. The following variables were measured before treatment as well as after 1, 3 and 6 months of treatment: factor VII activity, protein C activity, fibrinogen level, antithrombin III activity, plasminogen activator inhibitor-1 (PAI-1) level and the plasma concentration of tissue-type plasminogen activator (t-PA).

RESULTS

After 1 month of treatment, protein C activity increased by 9.6% and 11.4% of the initial value (p < 0.05), fibrinogen level decreased by 7.8% and 6.1% of the initial value (p < 0.05) and PAI-1 decreased by 19.4% and 14.3% of the initial value (p < 0.05) in the CEE therapy group and the CEE/MPA therapy group, respectively. Factor VII activity increased by 10.1% of the initial value (p < 0.05) in the CEE therapy group only. Antithrombin III and t-PA levels did not change throughout either treatment.

CONCLUSION

Except for an increase in factor VII activity in the case of continuous CEE therapy, continuous HRT had no unfavorable effects on either coagulation factors or fibrinolytic components.

Decreased plasma tissue factor pathway inhibitor in women taking combined oral contraceptives

Use of combined oral contraceptives (OC) is associated with a significant risk of thrombosis. The mechanisms of this effect are not clearly defined. Tissue factor pathway inhibitor (TFPI) is a circulating anti-coagulant that inhibits the earliest steps in activation of the extrinsic coagulation pathway. It plays a central role in control of coagulation but its contribution to the thrombotic risk associated with OC has not been assessed. Plasma TFPI antigen and activity, factor VIIa, prothrombin fragments 1&2, von Willebrand antigen, fibrinogen, and low density lipoprotein cholesterol were measured by standard assays in women taking OC (aged 16 to 45 years, n = 40) and age-matched women not taking OC (controls, n = 40). Plasma TFPI antigen did not vary significantly across the menstrual cycle in controls. Women on OC had a 25% reduction in plasma TFPI antigen (median 51.0 ng/ml; 95% confidence intervals [CI] 37.5 to 85.5; control 68.0 ng/ml, CI 61.0 to 95.0; P < 0.001) and a 29% reduction in TFPI activity (78.5 U/ml, CI 57.5 to 107.5; control 111.0 U/ml, CI 79.5 to 171.0; P < 0.001) compared to controls. Plasma factor VIIa activity and prothrombin fragments 1&2 were also significantly increased in women using OC (both P < 0.001), indicating activation of the extrinsic coagulation pathway. These results demonstrate that normal cyclic variations in estrogen and/or progesterone do not significantly alter plasma TFPI levels. However, estrogens and/or progestogens in OC result in activation of the extrinsic coagulation pathway and significantly reduce plasma TFPI, its major circulating inhibitor. Reduced plasma TFPI levels may underlie the thrombotic effects of OC.

Cardiovascular risks: perception versus reality

The high estrogen doses in the original oral contraceptive (OC) formulations were associated with an increased risk of cardiovascular events. Since then the steroid doses in OC have been reduced steadily, so that current low-estrogen-dose (< or = 35 micrograms) combination OC are associated with a lower risk of arterial and venous events than occurs with higher-estrogen-dose formulations. Based on the currently available epidemiologic evidence, the following conclusions can be made regarding the cardiovascular disease risks associated with use of low-dose OC by healthy, nonsmoking women: there is no increased risk of myocardial infarction (MI) or hemorrhagic or ischemic stroke; and there is a three- to fourfold increased risk of venous thrombosis and embolism (VTE). This risk is about half that associated with pregnancy. Smoking is the most important independent risk factor for MI, and is synergistic with OC use. Women smokers should be advised strongly to stop smoking, but those aged < 35 years may use any OC containing < or = 35 micrograms of estrogen. Women smokers aged > or = 35 years should be advised to use a nonestrogen or nonhormonal contraceptive method.

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.

Norethisterone Treatment, a Major Risk-Factor for Veno-Occlusive Disease in the Liver After Allogeneic Bone Marrow Transplantation

In this single-center study, we retrospectively analyzed incidence and risk factors for hepatic veno-occlusive disease (VOD) in 249 consecutive patients who underwent allogeneic hematopoietic stem cell transplantation between January 1990 and June 1995. Twenty-four of the 249 transplanted patients developed VOD. The probabilities of developing VOD were 17% among women and 7% in men (P = .01). In women treated with norethisterone, the incidence was 27% compared with 3% in women without this treatment (P = .007). One-year survival rates were 17% and 73% in patients with (n = 24) or without VOD (n = 225), respectively. The use of heparin prophylaxis (100 IE/kg/24 hours for 1 month) did not alter the incidence or 1-year mortality of VOD. In multivariate analysis, the following risk factors were significant: norethisterone treatment (P < .001), bilirubin >26 μmol/L before bone marrow transplantation (BMT) (P = .002), one HLA-antigen mismatch (P = .003), previous abdominal irradiation (P = .02), and conditioning with busulphan (P = .02). Our conclusion is that norethisterone treatment should not be used in patients undergoing BMT and heparin prophylaxis did not affect the incidence or mortality of VOD.

Norethisterone Treatment, a Major Risk-Factor for Veno-Occlusive Disease in the Liver After Allogeneic Bone Marrow Transplantation

In this single-center study, we retrospectively analyzed incidence and risk factors for hepatic veno-occlusive disease (VOD) in 249 consecutive patients who underwent allogeneic hematopoietic stem cell transplantation between January 1990 and June 1995. Twenty-four of the 249 transplanted patients developed VOD. The probabilities of developing VOD were 17% among women and 7% in men (P = .01). In women treated with norethisterone, the incidence was 27% compared with 3% in women without this treatment (P = .007). One-year survival rates were 17% and 73% in patients with (n = 24) or without VOD (n = 225), respectively. The use of heparin prophylaxis (100 IE/kg/24 hours for 1 month) did not alter the incidence or 1-year mortality of VOD. In multivariate analysis, the following risk factors were significant: norethisterone treatment (P &lt; .001), bilirubin &gt;26 μmol/L before bone marrow transplantation (BMT) (P = .002), one HLA-antigen mismatch (P = .003), previous abdominal irradiation (P = .02), and conditioning with busulphan (P = .02). Our conclusion is that norethisterone treatment should not be used in patients undergoing BMT and heparin prophylaxis did not affect the incidence or mortality of VOD.

Stroke and use of low-dose oral contraceptives in young women: a pooled analysis of two US studies

BACKGROUND AND PURPOSE

The available data on low-dose oral contraceptive pill (OCP) use and stroke risk in US women are limited by small numbers. We sought more precise estimates by conducting a pooled analysis of data from 2 US population-based case-control studies.

METHODS

We analyzed interview data from 175 ischemic stroke cases, 198 hemorrhagic stroke cases, and 1191 control subjects 18 to 44 years of age.

RESULTS

For ischemic stroke, the pooled odds ratio (pOR) adjusted for stroke risk factors for current use of low-dose OCPs compared with women who had never used OCP (never users) was 0.66 (95% confidence interval [CI], 0.29 to 1.47) and compared with women not currently using OCPs (nonusers) the pOR was 1.09 (95% CI, 0.54 to 2.21). For hemorrhagic stroke, the pOR for current use of low-dose OCPs compared with never users was 0.95 (95% CI, 0.46 to 1.93) and compared with nonusers the pOR was 1.11 (95% CI, 0.61 to 2.01). The pORs for current low-dose OCP use and either stroke type were not elevated among women who were >/=35 years, cigarette smokers, obese, or not receiving medical therapy for hypertension. pORs for current low-dose OCP use were 2.08 (95% CI, 1. 19 to 3.65) for ischemic stroke and 2.15 (95% CI, 0.85 to 5.45) for hemorrhagic stroke among women reporting a history of migraine but were not elevated among women without such a history. Past OCP use (irrespective of formulation) was inversely related to ischemic stroke but unrelated to hemorrhagic stroke.

CONCLUSIONS

Women who use low-dose OCPs are, in the aggregate, not at increased risk of stroke. Studies are needed to clarify the risk of stroke among users who may be susceptible on the basis of age, smoking, obesity, hypertension, or migraine history.

Oral contraceptives and thrombosis: an overview of study methods and recent results

Studies of the associations between oral contraceptives and cardiovascular disease are limited by the extreme rarity of these problems among young women. There are no randomized, controlled trials, and the large, prospective cohort studies only have data regarding older oral contraceptive formulations that are now little used. Historical cohort studies that use record-linkage techniques to analyze data from computerized databases represent a new approach to assessing oral contraceptive use and thrombosis. The largest new studies, with the most sophisticated analyses, use the case-control design. A surprising result of the new studies was a difference in risk of thrombosis according to progestin type. Because these are observational rather than randomized studies, clinical factors influence the choice of oral contraceptive and may bias the study results. Controversy about the surprising results has stimulated additional analyses and critical reviews in an attempt to explain the associations.

Oral contraceptive use and myocardial infarction

Epidemiologic studies of current oral contraceptive (OC) use and myocardial infarction (MI) have been contradictory and confusing. This comprehensive review of the epidemiologic literature attempts to draw conclusions about the risk of myocardial infarction in oral contraceptive users, focusing on recent, methodologically rigorous studies of the topic. Recent studies are consistent in showing a higher relative risk of MI in current OC users who smoke compared with current OC users who do not smoke. Studies in aggregate suggest that the relative risk of MI is higher in current OC users with hypertension than in current OC users without hypertension. Recent studies do not show a relationship between higher estrogen dose and higher risk of MI, but the effect of estrogen dose and progestogen type and dose are difficult to separate. The limited data on the risk of MI in current users of low estrogen OC do not allow a firm conclusion about the possibility that progestogen type might affect the risk of MI in current users. Past OC use does not increase or decrease the risk of MI.

Newer oral contraceptives and the risk of venous thromboembolism

Research on the relationship between venous thromboembolism and the progestagen content of combined oral contraceptives has pointed to an increase in risk associated with products containing desogestrel and gestodene. Although many biases must have been at play in these nonexperimental studies, the errors that have been suggested and examined are not of a sufficient magnitude to account for the observed results. The most plausible explanation of the available data is that combined oral contraceptives containing desogestrel and gestodene carry a very small risk of venous thromboembolism, which exceeds the even smaller risk carried by products containing levonorgestrel. The position of norgestimate is uncertain.

Oral contraceptives and hormone replacement therapy do not increase the incidence of arterial thrombosis in a nonhuman primate model

Older oral contraceptive (OC) formulations containing high doses of potent synthetic estrogens and progestins are associated with increased risk of thrombosis. To examine the effects of current low-dose OC and hormone replacement therapy (HRT) regimens on arterial thrombosis, premenopausal and surgically postmenopausal cynomolgus monkeys were divided into four treatment groups. Premenopausal monkeys were given either no OCs or ethinyl estradiol and levonorgestrel as an OC at a dose equivalent to that currently given to women. Postmenopausal monkeys were given either no HRT or conjugated equine estrogens and medroxyprogesterone as an HRT at a dose equivalent to that currently given to women. The monkeys were fed an atherogenic diet containing these treatments for 27 to 30 months. At the end of this time, arterial thrombosis was evaluated with a standardized stenosis/injury procedure in the left carotid artery. Blood flow velocity was monitored for cyclic or permanent occlusive thrombosis. The current OC and HRT regimens did not increase the susceptibility of the artery wall to develop an occlusive thrombus following injury and stenosis. In fact, there was a reduction in the incidence of thrombosis in the OC animals compared with untreated controls. Increased amounts of atherosclerosis were associated with an increased incidence of occlusive arterial thrombosis. Several selected coagulation parameters [von Willebrand factor, protein C, lipoprotein(a), and platelet aggregation] did not appear to be associated with either the amount of atherosclerosis or incidence of arterial thrombosis.

Modern oral contraceptives and cardiovascular disease

We reviewed evidence that bears on the cardiovascular safety of combined oral contraceptives containing second- and third-generation progestogens and < 50 micrograms of estrogen. Recent epidemiologic studies indicate that current use of these formulations is associated with a smaller increase in the incidence of venous thromboembolism than earlier formulations. In some studies the increase for third-generation formulations containing desogestrel or gestodene was about 1.5 to 2 times that for second-generation formulations, but there is evidence that differences between users in underlying risk and likelihood of being diagnosed contributed to this result. Recent studies of myocardial infarction suggest a smaller increase in risk associated with modern formulations than with earlier ones; one study suggests a threefold increase for second-generation formulations and no increase for third-generation formulations, but the finding requires confirmation. Recent studies of stroke indicate little or no increase in risk for modern formulations among women without risk factors. We conclude that modern combined oral contraceptives are safer than earlier formulations with respect to cardiovascular disease, which occurs rarely in young women.