Oral contraceptives and venous thromboembolism. A case-control study

U.S. Medical Eligibility Criteria for Contraceptive Use, 2024

The 2024 U.S. Medical Eligibility Criteria for Contraceptive Use (U.S. MEC) comprises recommendations for the use of specific contraceptive methods by persons who have certain characteristics or medical conditions. These recommendations for health care providers were updated by CDC after review of the scientific evidence and a meeting with national experts in Atlanta, Georgia, during January 25-27, 2023. The information in this report replaces the 2016 U.S. MEC (CDC. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR 2016:65[No. RR-3]:1-103). Notable updates include 1) the addition of recommendations for persons with chronic kidney disease; 2) revisions to the recommendations for persons with certain characteristics or medical conditions (i.e., breastfeeding, postpartum, postabortion, obesity, surgery, deep venous thrombosis or pulmonary embolism with or without anticoagulant therapy, thrombophilia, superficial venous thrombosis, valvular heart disease, peripartum cardiomyopathy, systemic lupus erythematosus, high risk for HIV infection, cirrhosis, liver tumor, sickle cell disease, solid organ transplantation, and drug interactions with antiretrovirals used for prevention or treatment of HIV infection); and 3) inclusion of new contraceptive methods, including new doses or formulations of combined oral contraceptives, contraceptive patches, vaginal rings, progestin-only pills, levonorgestrel intrauterine devices, and vaginal pH modulator. The recommendations in this report are intended to serve as a source of evidence-based clinical practice guidance for health care providers. The goals of these recommendations are to remove unnecessary medical barriers to accessing and using contraception and to support the provision of person-centered contraceptive counseling and services in a noncoercive manner. Health care providers should always consider the individual clinical circumstances of each person seeking contraceptive services. This report is not intended to be a substitute for professional medical advice for individual patients; when needed, patients should seek advice from their health care providers about contraceptive use.

The use of hormonal contraceptives in fertility treatments: a committee opinion

The use of hormonal contraception can be considered to aid in the timing of assisted reproductive technology cycles, reduce the risk of ovarian cysts at in vitro fertilization cycle initiation, and optimize visualization before hysteroscopy.

[The Thromboembolism Risk with Combined Hormonal Contraceptives: Current Status and Prescribing Practice]

The Thromboembolism Risk with Combined Hormonal Contraceptives: Current Status and Prescribing Practice Abstract. The use of combined hormonal contraceptives (CHC) increases not only the risk for venous thromboembolism, but also for arterial thromboembolism. The risk for thromboembolism is the same for non-oral CHC (patches, vaginal rings) as for oral CHC. Risk factors such as age >35, obesity, smoking and a positive family history need to be recognized and considered in contraceptive counselling. Elaborate information concerning risks and benefits is mandatory. This applies to first-time as well as long-term users. Careful investigation of the history is required, and the risk factors need to be re-evaluated at yearly prescription. It is also very important to inform the patients about the early symptoms of thrombosis or pulmonary embolism, so that therapy can be started immediately. Apart from these risks, CHC may have beneficial effects on organs such as the ovaries, the endometrium and the general well-being for many women. When prescribing a CHC for the first time or when changing to another preparation, one should always weigh up whether certain benefits justify prescribing a preparation with a slightly higher risk of thrombosis compared to the second-generation pill or preparations with Estradiol/Nomegestrolacetat. Women who are already using a third-generation pill or a pill with drospirenone or cyproterone acetate and feel comfortable with it do not need to switch to another preparation (provided no new risk factors have arisen). For women with increased risks, i.e. several relative contraindications or one absolute contraindication, safe alternatives to CHC include progestogen-only preparations, intrauterine devices containing copper or levonorgestrel or, after family planning has been completed, surgical methods (sterilisation/vasectomy).

Progestin-only contraception and thromboembolism: A systematic review

BACKGROUND

Women with medical conditions associated with increased risk for thrombosis generally should not use estrogen-containing contraceptives; however, less is known about progestin-only contraceptives (POCs) and thrombosis risk.

OBJECTIVES

The objective was to identify evidence regarding the risk of venous thromboembolism (VTE) or arterial thromboembolism [stroke or acute myocardial infarction (AMI)] among women using POCs.

METHODS

We searched the PubMed database for all articles published from database inception through January 2016 for studies examining thrombosis among women using POCs. We included studies which examined women with medical conditions associated with thrombosis risk, as well as studies of women in the general population (either without these conditions or who were not specified to have these conditions). Hormonal contraceptives of interest included progestin-only pills (POPs), injectables, implants and levonorgestrel-releasing intrauterine devices (LNG-IUDs). Outcomes of interest included VTE, stroke and AMI.

RESULTS

There were 26 articles of good to poor quality that met inclusion criteria; 9 studies examined women with medical conditions and 20 examined women in the general population. Two studies found that, among smokers and women with certain thrombogenic mutations, use of depot medroxyprogesterone acetate (DMPA) had elevated odds of VTE compared with nonsmokers or those without mutations, although confidence intervals were wide and overlapped with odds among nonusers. One study found that, among women with previous VTE, use of POCs (including DMPA) was associated with a nonsignificant increased odds of recurrent VTE (all of which were among DMPA users); two other studies that examined POCs other than DMPA did not observe an association with recurrent VTE. Two studies found that use of DMPA among healthy women was also associated with increased odds of VTE. Two studies found that use of POCs for therapeutic indications was associated with increased odds of VTE. Studies did not find increased odds of VTE with POPs for contraceptive purposes, implants or LNG-IUDs nor were there increased odds of stroke or AMI with any POCs.

CONCLUSION

The majority of evidence identified by this systematic review did not suggest an increase in odds for venous or arterial events with use of most POCs. Limited evidence suggested increased odds of VTE with use of injectables (three studies) and use of POCs for therapeutic indications (two studies, one with POCs unspecified and the other with POPs). Any increase in risk likely translates to a small increase in absolute numbers of thrombotic events at the population level.

Combined hormonal contraception and the risk of venous thromboembolism: a guideline

While venous thromboembolism (VTE) is rare in young women of reproductive age, combined oral contraceptives increase the risk of VTE. In the patient in whom combined hormonal contraception is appropriate, it is reasonable to use any currently available preparation.

Effect of Age on Oral Contraceptive-Induced Venous Thrombosis

This study was undertaken to investigate the effect of age on oral contraceptive-induced venous thrombosis. All women seen in the University of Padua Department of Medical and Surgical Science who had had two courses of oral contraceptive therapy at different ages were included. A total of 28 subjects met these criteria. Fifteen patients had a congenital or acquired prothrombotic condition, whereas 13 women were normal subjects. The mean age at which thrombosis occurred was 33.3 and 36.3 years for women with or without a prothrombotic condition, respectively. The ages during which the women remained asymptomatic were 23.1 and 23.3 years for women with or without a predisposing defect, respectively. Thrombosis occurred, during the second course of oral contraceptive therapy, after the mean duration of 6.5 cycles or 18.4 cycles in women with or without prothrombotic defects, respectively. During the asymptomatic course, approximately the same number of women took old progestins or third-generation compounds. On the contrary, during the second period, 21 of 28 women took progestins with third-generation compounds. Age seems to plays an important role in oral contraceptive-induced venous thrombosis. In normal women, thrombosis occurred after a greater number of oral contraceptive cycles as compared with the women with prothrombotic defects. Because the majority of women took preparations that contained third-generation progestins during the second course of therapy, concomitant contributing effects of these compounds cannot be excluded.

Instrumental variable analysis as a complementary analysis in studies of adverse effects: venous thromboembolism and second-generation versus third-generation oral contraceptives

PURPOSE

A potentially useful role for instrumental variable (IV) analysis may be as a complementary analysis to assess the presence of confounding when studying adverse drug effects. There has been discussion on whether the observed increased risk of venous thromboembolism (VTE) for third-generation oral contraceptives versus second-generation oral contraceptives could be (partially) attributed to confounding. We investigated how prescribing preference IV estimates compare with conventional estimates.

METHODS

Women in the Clinical Practice Research Database who started a second-generation or third-generation oral contraceptive from 1989 to 2013 were included. Ordinary least squares and two-stage least squares regression were used to estimate risk differences in VTE. Cox regression and IV for Cox proportional hazards regression were used to calculate hazard ratios (HR). The instrument used was the proportion of prescriptions for third-generation oral contraceptives by the general practitioner in the year preceding the current prescription.

RESULTS

All analyses pointed in the direction of an increased VTE risk for third-generation oral contraceptives. The adjusted HR from the conventional Cox regression was 1.62 (95% confidence interval 1.16-2.27) and the fully adjusted HR from the IV Cox regression was 3.45 (95% confidence interval; 0.97-11.7), showing a larger risk and wider confidence intervals in the IV analysis.

CONCLUSIONS

The similarity in direction of results from the IV analyses and conventional analyses suggests that major confounding is unlikely. IV analysis can be a useful complementary analysis to assess the presence of confounding in studies of adverse drug effects in very large databases.

Hormonal contraception among electronic cigarette users and cardiovascular risk: a systematic review

BACKGROUND

Women who use combined hormonal contraceptives and cigarettes have an increased risk for cardiovascular (CV) events. We reviewed the literature to determine whether women who use hormonal contraceptives (HC) and electronic cigarettes (e-cigarettes) also have an increased risk.

STUDY DESIGN

Systematic review.

METHODS

We searched for articles reporting myocardial infarction (MI), stroke, venous thromboembolism, peripheral arterial disease or changes to CV markers in women using e-cigarettes and HC. We also searched for indirect evidence, such as CV outcomes among e-cigarette users in the general population and among HC users exposed to nicotine, propylene glycol or glycerol.

RESULTS

No articles reported on outcomes among e-cigarette users using HC. Among the general population, 13 articles reported on heart rate or blood pressure after e-cigarette use. These markers generally remained normal, even when significant changes were observed. In three studies, changes were less pronounced after e-cigarette use than cigarette use. One MI was reported among 1012 people exposed to e-cigarettes in these studies. One article on nicotine and HC exposure found both exposures to be significantly associated with acute changes to heart rate, though mean heart rate remained normal. No articles on propylene glycol or glycerol and HC exposure were identified.

CONCLUSION

We identified no evidence on CV outcomes among e-cigarette users using HC. Limited data reporting mostly acute outcomes suggested that CV events are rare among e-cigarette users in the general population and that e-cigarettes may affect heart rate and blood pressure less than conventional cigarettes. There is a need for research assessing joint HC and e-cigarette exposure on clinical CV outcomes.

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.

[DVT and combined oral contraceptives: update of the pluridisciplinary CNGOF-FNCGM-GEHT-SFMV group]

Thrombotic risk among combined oral contraceptives (COC) users has recently been debated following a court action initiated by a patient. Recent epidemiological data, as well as accumulating biological data underlying these data, have led French Health authorities to modify COC prescription and reimbursement modalities. A short synthesis is proposed by a multidisciplinary group of experts from four French societies (CGOF, FNCGM, GHT, and SFMV).

Types of combined oral contraceptives used by US women

BACKGROUND

We sought to estimate the prevalence of types of combined oral contraceptives (COCs) used among US women.

STUDY DESIGN

We analyzed interview-collected data from 12,279 women aged 15-44 years participating in the National Survey of Family Growth, 2006-2010. Analyses focused on COC use overall, by pill type, across sociodemographics and health factors.

RESULTS

The prevalence of current COC use (88 different brands) was 17%. The majority of COC users used earlier-formulation COCs: ≥30 mcg (67%) versus <30 mcg estrogen (33%), monophasic (67%) versus multiphasic (33%) dosages and traditional 21/7 (88%) versus extended/other cycle regimens (12%) regimens. Norgestimate (32%) and norethindrone (20%) were the most commonly used progestins. Sociodemographic, gynecological and health risk factors were associated with type of COC use.

CONCLUSION

Further investigation of specific COC use and of the factors associated with types of pills used among US women at the population level is needed.

Progestin-only contraceptive pill use among women in the United States

BACKGROUND

Progestin-only contraceptive pills (POPs) offer a safe and effective contraceptive option, particularly for women at increased risk of venous thromboembolism. However, the prevalence of POP use among women in the United States is unknown.

STUDY DESIGN

We analyzed population-based data from 12,279 women aged 15-44 years in the National Survey of Family Growth. Data were collected continuously from 2006 to 2010 by in-person, computerized household interviews. Analyses describe POP use across sociodemographic and reproductive characteristics and thromboembolic risk profiles.

RESULTS

Overall, 0.4% of all reproductive-aged women in the United States currently use POPs. POP use was higher among parous, postpartum and breastfeeding women than their counterparts (all p values<.001). Women at higher risk of thromboembolism (older, obese, diabetic or smoking women) had similar proportions of POP use as women without those risks.

CONCLUSION

POPs are rarely used by US women. While data on chronic disease were limited, our results suggest that relatively few women with increased risk of thromboembolism are considering POPs when choosing an oral contraceptive.

Oral contraceptives and venous thromboembolism: a systematic review and meta-analysis

BACKGROUND

An association between oral contraceptive (OC) use and venous thromboembolism (VTE) has long been recognized. However, no summary estimates of the increase in VTE risk associated with OC use have been available since 1995, and no meta-analyses have evaluated the VTE risk of new preparations containing drospirenone.

OBJECTIVE

The aim of the study was to carry out a meta-analysis to summarize existing evidence on the association between venous VTE and OC use, and to investigate how such an association may vary according to the type of OC, OC user characteristics, study characteristics and biases.

METHODS

Relevant cohort or case-control studies were searched in MEDLINE and other electronic databases up to May 2010, with no language restriction. Data were combined using a generic inverse-variance approach. Meta-regression in addition to stratification was used to explore potential predictors of the summary estimate of risk.

RESULTS

Sixteen cohort and 39 case-control studies were included in at least one comparison. Overall, the odds ratio (OR) of OC users versus non-users was 3.41 (95% CI 2.98, 3.92). This estimate was based upon nine cohort studies evaluating approximately 12 000 000 person-years, and 23 case-control studies including approximately 45 000 women. VTE risk for OC users was significantly lower in studies evaluating 'all VTE cases' than in those evaluating 'idiopathic VTE only' (OR 3.09 and 4.94, respectively). Among the carriers of genetic mutations G20210A and Factor V Leiden (FVL), OC users showed a significantly increased VTE risk compared with non-users (OR 1.63; 95% CI 1.01, 2.65, and OR 1.80; 95% CI 1.20, 2.71, respectively). When the newest OCs containing drospirenone were compared with non-drospirenone-containing OCs (except those containing levonorgestrel only), VTE risk did not significantly increase (OR 1.13; 95% CI 0.94, 1.35).

CONCLUSIONS

This meta-analysis confirms that OC use significantly increases VTE risk. The strength of this association, however, varies according to the generation of OC, type of outcome and presence of a genetic mutation, with ORs ranging from 3 to 5.

[Questionnaire for assessing the risk of venous thromboembolism in hospitalized surgical and non-surgical patients in the 4th Hungarian antithrombotic guideline entitled "Risk reduction and treatment of venous thromboembolism"]

A large proportion of hospitalized surgical and medical patients are at risk for venous thromboembolism. Depending on the type of surgical intervention, venous thrombosis develops in 15-60% of surgical patients without prophylaxis. Although venous thromboembolism is most often considered to be associated with recent surgery or trauma, 50 to 70% of symptomatic thromboembolic events and 70 to 80% of fatal pulmonary embolisms occur in nonsurgical patients. International and national registries show that the majority of at-risk surgical patients actually received the appropriate thromboembolic prophylaxis. However, despite of international and national recommendations, prophylaxis was not provided for a large proportion of at-risk medical patients. The rate of medical patients receiving prophylaxis should be increased, and appropriate thrombosis prophylaxis should be offered to at-risk medical patients. The thrombosis risk assessment is an important tool to identify patients at increased risk for venous thromboembolism, to simplify decision making on prophylaxis administration, and to improve the adherence to guidelines. When the risk is recognized, if there is no contraindication, prophylaxis should be ordered. The 4th Hungarian Antithrombotic Guideline entitled "Risk reduction and treatment of thromboembolism" calls attention to the importance of risk assessment and for the first time it includes and recommends risk assessment models for hospitalized surgical and medical patients. The risk assessment models are presented and the evidence based data for the different risk factors included in these models are reviewed.

The venous thrombotic risk of oral contraceptives, effects of oestrogen dose and progestogen type: results of the MEGA case-control study

OBJECTIVE

To assess the thrombotic risk associated with oral contraceptive use with a focus on dose of oestrogen and type of progestogen of oral contraceptives available in the Netherlands.

DESIGN

Population based case-control study.

SETTING

Six participating anticoagulation clinics in the Netherlands (Amersfoort, Amsterdam, The Hague, Leiden, Rotterdam, and Utrecht).

PARTICIPANTS

Premenopausal women <50 years old who were not pregnant, not within four weeks postpartum, and not using a hormone excreting intrauterine device or depot contraceptive. Analysis included 1524 patients and 1760 controls.

MAIN OUTCOME MEASURES

First objectively diagnosed episodes of deep venous thrombosis of the leg or pulmonary embolism. Odds ratios calculated by cross-tabulation with a 95% confidence interval according to Woolf's method; adjusted odds ratios estimated by unconditional logistic regression, standard errors derived from the model.

RESULTS

Currently available oral contraceptives increased the risk of venous thrombosis fivefold compared with non-use (odds ratio 5.0, 95% CI 4.2 to 5.8). The risk clearly differed by type of progestogen and dose of oestrogen. The use of oral contraceptives containing levonorgestrel was associated with an almost fourfold increased risk of venous thrombosis (odds ratio 3.6, 2.9 to 4.6) relative to non-users, whereas the risk of venous thrombosis compared with non-use was increased 5.6-fold for gestodene (5.6, 3.7 to 8.4), 7.3-fold for desogestrel (7.3, 5.3 to 10.0), 6.8-fold for cyproterone acetate (6.8, 4.7 to 10.0), and 6.3-fold for drospirenone (6.3, 2.9 to 13.7). The risk of venous thrombosis was positively associated with oestrogen dose. We confirmed a high risk of venous thrombosis during the first months of oral contraceptive use irrespective of the type of oral contraceptives.

CONCLUSIONS

Currently available oral contraceptives still have a major impact on thrombosis occurrence and many women do not use the safest brands with regard to risk of venous thrombosis.

Hormone therapy and thromboembolic disease

PURPOSE OF REVIEW

Hormone therapy increases the risk of venous thromboembolism (VTE). To reduce this risk, changes in dosage, composition and route of administration have been made over the years. This review provides a summary of the available evidence and an update on the most recent findings on the issue.

RECENT FINDINGS

Contraceptives containing third-generation progestagens confer a higher risk of VTE than second-generation compounds. Little data are available on preparations containing less than 30 micarog of estrogen, new progestagens or levonorgestrel-releasing intrauterine devices. Hormone replacement therapy increases the risk of VTE by 2 to 3-fold. Transdermal administration may be less thrombogenic than oral administration, while different estrogens and progestagens may carry a different risk. VTE risk is further increased in carriers of inherited thrombophilia. Despite a similar increase in relative risk of thrombosis associated with hormone therapy, absolute risk is lower in fertile women and higher in postmenopausal ones. Universal screening for thrombophilia before prescribing hormone replacement therapy might be cost-effective.

SUMMARY

Careful evaluation of individual risk factor is warranted before prescribing hormone therapy. Further investigations are needed to establish whether or not newer compounds are safer than older ones with respect to the risk of thrombosis.

Effects of oral and transvaginal ethinyl estradiol on hemostatic factors and hepatic proteins in a randomized, crossover study

CONTEXT

The use of combined hormonal contraceptives with ethinyl estradiol (EE) and a progestin results in alterations in potential biomarkers of venous thromboembolism risk. Evaluation of the impact of delivery route on these changes is difficult due to an interaction between EE and the progestin component.

OBJECTIVE

The aim of the study was to compare the impact of oral and vaginal administration of EE alone on hemostatic variables and estrogen-sensitive liver proteins.

DESIGN

This was a single-center, randomized, crossover study with two treatment cycles separated by a washout cycle.

SETTING

The study was conducted in an academic outpatient center.

PARTICIPANTS

Fourteen healthy postmenopausal women were enrolled; 13 completed the study and were included in the analyses.

INTERVENTION

Participants were randomized to receive EE (15 microg/d) delivered by oral tablet or vaginal ring for 21 d in one of two treatment sequences.

MAIN OUTCOME MEASURES

Changes in plasma concentration or activity of 10 hemostatic variables and six estrogen-sensitive liver proteins between baseline and d 21 of treatment were the primary outcomes.

RESULTS

Prothrombin fragment 1 + 2 plasma level was unaffected by treatment or delivery route. Angiotensinogen (expressed as plasma level of angiotensin I) increased similarly with oral and vaginal delivery; mean (sd) increases were 2757 (1033) and 2864 (893) ng /ml, respectively (P = 0.0002). Alterations in other study variables, except total cholesterol, were similar with oral and vaginal administration.

CONCLUSION

Our results provide evidence that the customary effects of combined hormonal contraceptives on hemostatic variables and estrogen-sensitive liver proteins are largely related to EE and independent of delivery route during short-term treatment.

Arterial thrombosis in young women after ovarian stimulation: case report and review of the literature

Both venous and arterial thrombosis have been described in women after ovarian stimulation and/or hyperstimulation for infertility management. The ratio between venous and arterial thrombosis in this condition is about 2 or 3 to 1, contrary to what seen during pregnancy or oral contraception where it is 5 or 10 to 1. An accurate perusal of the literature and of personal files has yielded 34 cases of arterial thrombosis after assisted reproductive technologies (ART) which entailed ovarian stimulation. There were 15 cases of ischemic strokes; 7 cases of carotid and/or vertebral artery occlusion; 6 of aorta and peripheral vessel thrombosis, 2 of mesenteric artery occlusion, 3 with myocardial infarction and 2 with intracardiac thrombosis. Associated risk factors were as follow: smoking in 4 women; antiphospholipid antibodies in 2; decrease in protein S in 1. Furthermore, polycystic ovaries were present in two women. Ovarian hyperstimulation was obtained with several protocols which included human chorionic gonadotropin (HCG) in all but a few instances. Age of women varied between 22 and 41 with an average of 32. Nineteen women were pregnant at the time of thrombosis. Only seven of these 19 pregnancies were brought to term with fetal survival. Abortion was spontaneous in 5 cases and therapeutic in the additional 7. There were two maternal fatalities.

Exogenous Sex Hormones and Thrombophilia

Worldwide, hundreds of millions of women use exogenous estrogens in contraceptives or for postmenopausal hormone replacement. Exogenous estrogens increase the risk for venous and arterial thrombosis. This article reviews the use of exogenous sex hormones in women with thrombophilia.

Effect of Factor V Leiden and prothrombin G20210-->A mutations on thromboembolic risk in the national surgical adjuvant breast and bowel project breast cancer prevention trial

BACKGROUND

In the National Surgical Adjuvant Breast and Bowel Project's Breast Cancer Prevention Project (BCPT), tamoxifen use was associated with an increased relative risk for venous thromboembolic events, including deep vein thrombosis and pulmonary emboli, compared with placebo. However, the involvement of hypercoagulability factors in this association is unclear.

METHODS

To examine possible associations among the risk of venous thromboembolic events, tamoxifen use, and Factor V Leiden (FVL) and prothrombin G20210-->A (PT20210) mutations, which are involved in promoting blood coagulation, we used a nested, matched, case-control (1 : 4) design and compared women in the BCPT who had experienced venous thromboembolic events (n = 76) with women who did not (n = 295). FVL and PT20210 mutations were detected in genomic DNA that was isolated from blood samples collected at trial enrollment.

RESULTS

Venous thromboembolic events occurred in 28 women (deep vein thrombosis in 22 and pulmonary emboli in six) who were taking placebo and in 53 women (deep vein thrombosis in 35 and pulmonary emboli in 18) who were taking tamoxifen (relative risk = 1.90, 95% confidence interval = 1.18 to 3.12). Excessive risk for venous thromboembolic events was observed only in the first 36 months of therapy. There were no differences in age, smoking, and race between the groups, but women with venous thromboembolic events had a higher body mass index than women without (mean +/- standard deviation, 30 kg/m(2) +/- 7.7 versus 27.1 +/- 5.6; P<.001). FVL and/or PT20210 mutations were found in nine women (four on tamoxifen and five on placebo) with venous thromboembolic events and in 20 control subjects (nine on tamoxifen and 11 on placebo). No associations were found between risk of venous thromboembolic events and mutation status in either treatment group.

CONCLUSIONS

Venous thromboembolic disease in the BCPT women is associated with tamoxifen use and body mass index, but not with FVL and PT20210 mutations. Screening women at risk for breast cancer for FVL and/or PT20210 appears to offer no benefit in determining the risk of tamoxifen-associated thromboembolic events.

Ovarian Hormones and Migraine Headache: Understanding Mechanisms and Pathogenesis-Part 2

Migraine headache is strongly influenced by reproductive events that occur throughout the lifespan of women. Each of these reproductive events has a different "hormonal milieu," which might modulate the clinical course of migraine headache. Estrogen and progesterone can be preventative or provocative for migraine headache under different circumstances depending on their absolute serum levels, constancy of exposure, and types of estrogen/progesterone derivatives. Attacks of migraine with and without aura respond differently to changes in ovarian hormones. Clearly a greater knowledge of ovarian hormones and their effect on migraine is essential to a greater understanding of the mechanisms and pathogenesis of migraine headache.

Potential impact of oral contraceptive choice on myocardial infarction mortality and deep vein thrombosis

OBJECTIVES

To summarise the epidemiological evidence on the relationship between second- (OC2) and third-generation (OC3) oral contraceptives (OC) and the mortality associated with deep vein thrombosis (DVT) and myocardial infarction (MI), and to extrapolate and balance the evidence for these risks to the population of French OC users.

METHODS

All studies published on the risk of MI during OC2 and OC3 use were analysed. For DVT the Committee for Proprietary Medicinal Products public assessment report published in 2001 and more recent studies published on this topic were used. The estimates of odds ratios (OR) for risk of death from DVT or MI were extracted from the published manuscripts. ORs were used to calculate the aetiological fraction of risk for death from DVT and MI in the population; the relative impact of OC3 compared to OC2 use was expressed as an excess risk of death overall and by age group for French women.

RESULTS

Compared with OC2, the use of OC3 would prevent a maximum of 24 deaths from MI per year and induce a maximum of 16 deaths. Conversely, OC3 would induce 282-940 excess cases of DVT per year, resulting in 28-94 pulmonary embolisms and 3-19 deaths in the 4.7 million French OC users.

CONCLUSION

Balancing the evidence, it is difficult to conclude that the overall cardiovascular risk is significantly lower for either of the two OC schemes.

Pharmacogenetic aspects of the use of oral contraceptives and the risk of thrombosis

Oral contraceptives are currently used by more than 100 million women in developed countries and are a highly efficacious method to prevent undesired pregnancies. However, oral contraceptives are associated with an increased risk of venous and arterial thrombosis, through changes in blood coagulation and fibrinolysis. In order to reduce such complications, the composition of oral contraceptives has changed over the past decades, both for the dose of oestrogen and the type of progestagen. However, the risk for venous thromboembolism remains, particularly for women who are carriers of inherited thrombophilia. In these women, prescription of oral contraceptives should be carried out on an individual basis. This review illustrates the risk of thrombosis, particularly venous thromboembolism, associated with the use of oral contraceptives, underlines the crucial role of the interaction of these drugs with other risk factors for the disease, and gives suggestions on the utility of thrombophilia screening before prescription.

Pulmonary embolism associated with combined oral contraceptives: reporting incidences and potential risk factors for a fatal outcome

BACKGROUND

It is established that combined oral contraceptive (COC) treatment increases the risk of a pulmonary embolism (PE), but specific risk factors for a fatal outcome from a PE remain to be determined. This study aimed to identify such risk factors, and to calculate the reporting rates of fatal and non-fatal PE.

METHODS

Cases of suspected PE during treatment with COCs reported to the Swedish Adverse Drug Reactions Advisory Committee (SADRAC) between 1965 and 2001 were included. Medical records were scrutinized for potential risk factors for a venous thromboembolism (VTE). Annual sales data were obtained from the National Corporation of Pharmacies.

RESULTS

A total of 248 cases of a suspected PE were reported; 207 non-fatal and 41 fatal. A VTE was verified in all fatal, and in 83.5% of non-fatal cases. The presence of nausea or abdominal pain, an age >35 years, concomitant treatment with other drugs which may increase the VTE risk, vein or lymph vessel malformation, and a deep vein thrombosis above the knee level were positively associated with a fatal outcome. Chest pain and previous COC use were negatively associated with a fatal outcome. The reporting rate of a PE with a verified VTE was 1.72 (95% confidence interval 1.47-2.00) cases per 100 000 treatment years, and of a fatal PE 0.25 (95% confidence interval 0.16-0.37) cases per 100 000 treatment years.

CONCLUSION

Several specific potential risk factors for a fatal outcome from a COC-induced PE were identified. Recognition of these in combination with a high suspicion of VTE in COC users may reduce the risk of a fatal outcome.

Estrogen-containing oral contraceptives are allowable in young women with factor V Leiden heterozygosity without a history of thrombosis

An 18-year-old woman without significant past medical and surgical history presents to discuss the safety and efficacy of oral contraceptives. She is sexually active and currently relying on condoms alone for birth control. Her cousin had a deep venous thrombosis (DVT) following a pregnancy. As part of the family screening, this patient was identified as a factor V Leiden heterozygote. The risks and benefits of initiating oral contraceptives are discussed.

Low-dose oral contraceptive effects on thromboelastogram criteria and relationship to hypercoagulability

OBJECTIVE

The study was undertaken to assess hypercoagulability, by using thromboelastography, in women who use low-dose oral contraceptives (OCs).

STUDY DESIGN

Forty-three women using low-dose OCs (<or=35 microg ethinyl estradiol) underwent thromboelastography before starting OCs and again during the third month of OC use. Prior and 3-month mean values of four thromboelastogram parameters (maximum amplitude [MA], K time, alpha angle, and R time) were compared by using paired t tests. Comparison according to progestin type was also performed with unpaired t tests.

RESULTS

Prior versus 3-month values for MA, alpha, and K were not significantly different (P values-K: 0.8; alpha:.34; MA: 0.49); power was adequate to detect small differences. The 3-month R time was decreased compared with pre-OC values (P =.025), although the magnitude of this change was not characteristic of hypercoagulability. Comparison according to progestin type demonstrated no difference.

CONCLUSION

We found no significant trend toward hypercoagulability in women who used low-dose OCs and who otherwise had no known thromboembolic risks.

Thrombophilias and gynaecology

In gynaecology, women are exposed to sex steroids when using oral contraceptives, hormone replacement therapy or when undergoing in vitro fertilization treatment and ovulation induction. Oral contraceptives and the use of hormone replacement therapy increase the risk of venous thrombosis. The risk is highest in the first year of use and higher among women with clotting defects. Women taking third-generation oral contraceptives have an almost twofold increased risk of venous thrombosis compared with those taking second-generation oral contraceptives. Inherited clotting defects, which are themselves risk factors of venous thrombosis, (e.g. factor V Leiden mutation, deficiency of protein C, protein S or antithrombin, high plasma levels of factor VIII, and prothrombin mutation) appear synergistically increase the risk of venous thrombosis caused by oral contraceptives. Recent studies also point to an interaction between hormone replacement therapy and coagulation defects in causing venous thrombosis. Emerging studies show that in vitro fertilization treatment and ovulation induction are also risk factors for venous thrombosis; the role of coagulation defects in this association is not yet clear.

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.

Laboratory evaluation of hypercoagulability with venous or arterial thrombosis

OBJECTIVE

To provide recommendations for hypercoagulation testing for patients with venous, arterial, or neurovascular thrombosis, as reflected in the medical literature and the consensus opinion of recognized experts in the field.

DATA SOURCES, EXTRACTION, AND SYNTHESIS

The authors extensively examined the literature and current practices, and prepared a draft manuscript with preliminary recommendations. The draft manuscript was circulated to each of the expert participants (n = 30) in the consensus conference prior to the convening of the conference. The manuscript and recommendations were then presented at the conference for discussion. Recommendations were accepted if a consensus of the 28 experts attending the conference was reached. The discussions were also used to revise the manuscript into its final form.

CONCLUSIONS

The resulting article provides 17 recommendations for hypercoagulation testing in the setting of venous, arterial, or neurovascular thrombosis. The supporting evidence for test selection is analyzed and cited, and consensus recommendations for test selection are presented. Issues for which a consensus was not reached at the conference are also discussed.

Termination of pregnancy following panic-stopping of oral contraceptives

This study assessed characteristics of women presenting for termination of pregnancy subsequent to stopping combined oral contraceptive use in response to publicity-mediated fears regarding venous thromboembolism. Records of 400 women attending for pregnancy termination assessment were reviewed retrospectively. Panic-stopping of oral contraceptives was implicated in 9.5%. Nearly 50% of combined pill users claimed their pregnancy resulted from panic-stopping because of media-promoted fear of health risks, especially 'clots.' Panic-stoppers had significantly lower identified risk factors for venous thromboembolism than pill users who had not panic-stopped. The relative safety of third-generation pills is under debate. The risk-benefit ratio of contraceptive pills is overwhelmingly positive but practitioners must be vigilant in screening for risk factors and contraindications. Panic-stopping results in unwanted pregnancies with concomitant psychological distress and potential physical morbidity. In future situations where research findings may precipitate drug scares, we recommend recall of patients by their health provider, funded by the relevant health authority or pharmaceutical companies, to allow discussion of risks before the media is enabled to have access to the information.

Oral contraceptives and venous thromboembolism: a five-year national case-control study

The objective of this study was to assess the influence of oral contraceptives (OCs) on the risk of venous thromboembolism (VTE) in young women. A 5-year case-control study including all Danish hospitals was conducted. All women 15-44 years old, suffering a first ever deep venous thrombosis or a first pulmonary embolism (PE) during the period January 1, 1994, to December 30, 1998, were included. Controls were selected annually, 600 per year in 1994-1995 and 1200 per year 1996-1998. Response rates for cases and controls were 87.2% and 89.7%, respectively. After exclusion of nonvalid diagnoses, pregnant women, and women with previous thrombotic disease, 987 cases and 4054 controls were available for analysis. A multivariate, matched analysis was performed. Controls were matched to cases within 1-year age bands. Adjustment was made for confounding influence (if any) from the following variables: age, year, body mass index, length of OC use, family history of VTE, cerebral thrombosis or myocardial infarction, coagulopathies, diabetes, years of schooling, and previous birth. The risk of VTE among current users of OCs was primarily influenced by duration of use, with significantly decreasing odds ratios (OR) over time: <1 year, 7.0 (5.1-9.6); 1-5 years, 3.6 (2.7-4.8); and >5 years, 3.1 (2.5-3.8), all compared with nonusers of OCs. After adjustment for confounders, current use of OCs with second- (levonorgestrel or norgestimate) and third- (desogestrel or gestodene) generation progestins when compared with nonuse resulted in ORs for VTE of 2.9 (2.2-3.8) and 4.0 (3.2-4.9), respectively. After adjusting for progestin types and length of use, the risk decreased significantly with decreasing estrogen dose. With 30-40 microg as reference, 20 and 50 microg products implied ORs of 0.6 (0.4-0.9) and 1.6 (0.9-2.8), respectively (p(trend) = 0.02). After correction for duration of use and differences in estrogen dose, the third/second-generation risk ratio was 1.3 (1.0-1.8; p <0.05). In conclusion, use of OCs was associated significantly to the risk of VTE. The risk among current users was reduced by more than 50% during the first years of use. The risk increased more than 100% with increasing estrogen dose, and the difference in risk between users of third- and second-generation OCs, after correction for length of use and estrogen dose, was 33%.

Female hormones and thrombosis

Exogenous hormones are used by more than a hundred million women worldwide as oral contraceptives or for postmenopausal hormone replacement. Oral contraceptives increase the risk of venous thrombosis, of myocardial infarction, and of stroke. The risk is highest during the first year of use. The venous thrombotic risk of oral contraceptives is high among women with coagulation abnormalities and with so-called third-generation contraceptives (containing desogestrel or gestodene). The risk of myocardial infarction does not appear to depend on coagulation abnormalities or the type of oral contraceptive. Hormone replacement therapy increases the risk of venous thrombosis. This risk is also highest in the first year of use and among women with coagulation abnormalities. The risk becomes very high in women with a previous venous thrombosis. Randomized trials have not confirmed a beneficial effect of postmenopausal hormones on the occurrence of myocardial infarction.