Hormonal contraception (HC) is widely used throughout the world and has been associated with venous thrombosis (VT) such as deep vein thrombosis, pulmonary emboli, and cerebral VT.
Objectives
To provide a current comprehensive overview of the risk of objectively confirmed VT with HC in healthy women compared to nonusers.
Search Methods
PubMed was searched from inception to April 2018 for eligible studies in the English language, with hand searching from past systematic reviews.
Selection Criteria
We selected original research evaluating risk of objectively confirmed VT in healthy women taking oral or nonoral HC compared with nonusers.
Data Collection
The primary outcome of interest was a fatal or nonfatal VT in users of HC compared to nonusers or past users. Studies with at least twenty events were eligible. Adjusted relative risks with 95 percent confidence intervals were reported. Three independent reviewers extracted data from selected studies.
Results
1,962 publications were retrieved through the search strategy, with 15 publications included. Users of oral contraception with levonorgesterol had increased risk of VT by a range of 2.79-4.07, while other oral hormonal preparations increased risk by 4.0-48.6. Levonorgestrel intrauterine devices did not increase risk. Etonogestrel/ethinyl estradiol vaginal rings increased the risk of VT by 6.5. Norelgestromin/ethinyl estradiol patches increased risk of VT by 7.9. Etonogestrel subcutaneous implants by 1.4 and depot-medroxyprogesterone by 3.6. The risk of fatal VT was increased in women aged fifteen to twenty-four by 18.8-fold.
Conclusion
Users of HC have a significant increased risk of VT compared to nonusers. Current risks would project at least 300-400 healthy young women dying yearly in the United States due to HC. Women should be informed of these risks and offered education in fertility-awareness-based methods with comparable efficacy for family planning.
Summary
HC is widely used throughout the world and has been associated with blood clots in the legs and lungs. We searched the literature and found the risks of currently used forms of birth control increased between threeand ninefold for blood clots for healthy women. The risks found would project 300-400 women dying from using HC each year in the United States.
PMID 32431379 32431379 DOI 10.1177/0024363918816683 10.1177/0024363918816683 Keenan et al. 2018, Keenan 2018
Cite this article
Keenan, L., Kerr, T., Duane, M., & Van Gundy, K. (2018). Systematic Review of Hormonal Contraception and Risk of Venous Thrombosis. The Linacre Quarterly, 85(4), 470-477. https://doi.org/10.1177/0024363918816683
Keenan L, Kerr T, Duane M, Van Gundy K. Systematic Review of Hormonal Contraception and Risk of Venous Thrombosis. Linacre Q. 2018;85(4):470-477. doi:10.1177/0024363918816683
Keenan, L., et al. "Systematic Review of Hormonal Contraception and Risk of Venous Thrombosis." The Linacre Quarterly, vol. 85, no. 4, 2018, pp. 470-477.
This paper reviews the risk of thrombosis with use of different types of hormonal contraception in women of different ages. Combined hormonal contraceptives with desogestrel, gestodene, drospirenone or cyproterone acetate (high-risk products) confer a sixfold increased risk of venous thromboembolism as compared with nonusers, and about twice the risk as compared with users of products with norethisterone, levonorgestrel or norgestimate (low-risk products). Transdermal patches and vaginal ring belong to high-risk products. The risk of thrombotic stroke and myocardial infarction is increased 50 - 100% with use of combined products, with little difference in risk between different progestins. Progestin-only products do not confer any increased risk of venous or arterial thrombosis, except for progestin depot, which may double the risk of venous thrombosis. EXPERT Opinion: First choice in women below 35 years should be a combined low-risk pill, that is, with a second-generation progestin, with the lowest compliable dose of estrogen. Young women with risk factors of thrombosis such as age above 35 years, genetic predispositions, adiposity, polycystic ovary syndrome, diabetes, smoking, hypertension or migraine with aura should not use high-risk products, but should primarily consider progestin-only products, and be careful to use low-risk combined products.
Combined hormonal contraceptives (CHCs) place women at increased risk of venous thromboembolic events (VTEs) and arterial thrombotic events (ATEs), including acute myocardial infarction and ischemic stroke. There is concern that three recent CHC preparations [drospirenone-containing pills (DRSPs), the norelgestromin-containing transdermal patch (NGMN) and the etonogestrel vaginal ring (ETON)] may place women at even higher risk of thrombosis than other older low-dose CHCs with a known safety profile. All VTEs and all hospitalized ATEs were identified in women, ages 10-55 years, from two integrated health care programs and two state Medicaid programs during the time period covering their new use of DRSP, NGMN, ETON or one of four low-dose estrogen comparator CHCs. The relative risk of thrombotic and thromboembolic outcomes associated with the newer CHCs in relation to the comparators was assessed with Cox proportional hazards regression models adjusting for age, site and year of entry into the study. The hazards ratio for DRSP in relation to low-dose estrogen comparators among new users was 1.77 (95% confidence interval 1.33-2.35) for VTE and 2.01 (1.06-3.81) for ATE. The increased risk of DRSP was limited to the 10-34-year age group for VTE and the 35-55-year group for ATE. Use of the NGMN patch and ETON vaginal ring was not associated with increased risk of either thromboembolic or thrombotic outcomes. In new users, DRSP was associated with higher risk of thrombotic events (VTE and ATE) relative to low-dose estrogen comparator CHCs, while the use of the NGMN patch and ETON vaginal ring was not.
contraception/adverse-effects/venous-thromboembolismtherapeutics/prescribing-safety/medication-safety-in-pregnancy
Open Access
To assess the risk of venous thrombosis in current users of non-oral hormonal contraception.
Historical national registry based cohort study.
Four national registries in Denmark. All Danish non-pregnant women aged 15-49 (n=1,626,158), free of previous thrombotic disease or cancer, were followed from 2001 to 2010. Incidence rate of venous thrombosis in users of transdermal, vaginal, intrauterine, or subcutaneous hormonal contraception, relative risk of venous thrombosis compared with non-users, and rate ratios of venous thrombosis in current users of non-oral products compared with the standard reference oral contraceptive with levonorgestrel and 30-40 µg oestrogen. Diagnoses were confirmed by at least four weeks of anticoagulation therapy after the diagnosis. Within 9,429,128 woman years of observation, 5287 first ever venous thrombosis events were recorded, of which 3434 were confirmed. In non-users of hormonal contraception the incidence rate of confirmed events was 2.1 per 10,000 woman years. Compared with non-users of hormonal contraception, and after adjustment for age, calendar year, and education, the relative risk of confirmed venous thrombosis in users of transdermal combined contraceptive patches was 7.9 (95% confidence interval 3.5 to 17.7) and of the vaginal ring was 6.5 (4.7 to 8.9). The corresponding incidences per 10,000 exposure years were 9.7 and 7.8 events. The relative risk was increased in women who used subcutaneous implants (1.4, 0.6 to 3.4) but not in those who used the levonorgestrel intrauterine system (0.6, 0.4 to 0.8). Compared with users of combined oral contraceptives containing levonorgestrel, the adjusted relative risk of venous thrombosis in users of transdermal patches was 2.3 (1.0 to 5.2) and of the vaginal ring was 1.9 (1.3 to 2.7). Women who use transdermal patches or vaginal rings for contraception have a 7.9 and 6.5 times increased risk of confirmed venous thrombosis compared with non-users of hormonal contraception of the same age, corresponding to 9.7 and 7.8 events per 10,000 exposure years. The risk was slightly increased in women using subcutaneous implants but not in those using the levonorgestrel intrauterine system.
Hormonal contraceptives have been on the market for over fifty years and, while their formulations have changed, the basic mechanism of action has remained the same. During this time, numerous studies have been performed documenting side effects, some of which appear over time, some within weeks or months, but all can have a serious impact on health and quality of life. An effort was made to perform a series of comprehensive literature surveys to better understand immediate and long-term side effects of these agents. The results of this literature review uncovered a number of potential side effects, some of which are acknowledged and many of which are not noted in the prescribing information for these agents. Among the unacknowledged side effects are: an increased risk of HIV transmission for depot medroxyprogesterone acetate (DMPA), and for combination contraceptives breast cancer, cervical cancer, Crohn's disease, ulcerative colitis, systemic lupus erythematosus, depression, mood disorders and suicides (especially among women twenty-five years of age and younger, in the first six months of use), multiple sclerosis, interstitial cystitis, female sexual dysfunction, osteoporotic bone fractures (especially for progesterone-only contraceptives), and fatty weight gain. Misleading prescribing information regarding cardiovascular and thrombotic risks are also noted. Women seeking birth control have a right to be informed and educated about risk avoidance through the use of effective nonhormonal methods like fertility awareness methods. In one case-that of DMPA-the increased risk of HIV acquisition has been conclusively demonstrated to be both real and unique to this drug. Considering the availability of numerous alternatives, there is no justification for the continued marketing of DMPA to the public.
We reviewed the effect of hormonal contraceptives on women's health. A number of potential side effects were noted including increased risks of breast cancer, cervical cancer, inflammatory bowel disease, lupus, multiple sclerosis, cystitis, bone fractures, depression, mood disorders and suicides, fatty weight gain, and female sexual dysfunction. With the long-acting injectable contraceptives there is an increased risk of getting HIV. Misleading prescribing information regarding the risks of heart attacks, strokes and blood clotting problems were also noted. Women seeking birth control have a right to know about how to avoid these risks by using effective hormone-free Fertility Awareness Methods.