Birth Control Risks
Increased Risk of Blood Clots With Newer Birth Control Methods?
Print This Post
Your female patients are likely to ask you about a new study released by the U.S. Food and Drug Administration (FDA)[1] showing that women taking certain brands of birth control pills are 75% more likely to develop a blood clot.
The data are from a study that used four geographically diverse health plans which included more than 835,000 women who used one of four different types of birth control between 2001 and 2007.
After analyzing the medical history of all the women and adjusting for age and length of use, the research team was able to make an association between the type of birth control used and the risk of developing a venous thromboembolism (VTE). On average, women who used birth control pills (BCPs) containing the fourth-generation synthetic hormone drospirenone were 75% more likely to experience a VTE than women taking BCPs with levonorgestrel, an older medication. Medications containing drospirenone include Yaz®, Yasmin®, Beyaz®, Safyral™ (Bayer), and Loryna™ (Sandoz), as well as various generic forms of these medications.
In the analysis, the FDA also reported higher risks of blood clots in women using the Ortho Evra® patch (Johnson & Johnson) and the NuvaRing® vaginal ring (Merck & Co.). Both of these forms of birth control combine estrogen—which is present in all birth control pills—with two other fourth-generation synthetic hormones launched in the past decade. The FDA study was released the same week as a very large Danish study published in the BMJ. The BMJ study, which included more than one million Danish women, found that women taking Yaz and two other fourth-generation BCPs had twice the risk of blood clots as women taking the older hormone levonorgestrel.[2]
The analysis is also drilled down to look at the use of the four contraceptives by age. The risk of VTE for all three study contraceptives was higher in the younger age groups (10-34 years) than in older age groups (35-55 years) for all users; however, a significant risk for drospirenone was noted only in women aged 35 and older.
Of note is that four previously published studies have also addressed the risk of blood clots in women using BCPs containing drospirenone. These studies had conflicting findings—two post-marketing studies required by the FDA and European regulatory agencies did not report any difference in the risk of blood clots between drospirenone-containing products and products containing levonorgestrel or other progestins. Two other publications in 2009, however, reported that the risk of blood clots is up to two times greater in women using drospirenone-containing products than in women who use levonorgestrel-containing products. Information from these latter four studies is already presented in the Warnings and Precautions section of current labels for birth control pills that contain drospirenone.
The FDA says the findings from the study will be presented and discussed at the joint meeting of the Reproductive Health Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee on December 8, 2011.
To ensure patients are aware of the possible risks of these birth control pills, the FDA suggests the following:
- For women who are new to BCPs, consider starting with an older-generation pill.
- Patients should know the symptoms of blood clots, including persistent leg pain, severe chest pain, or sudden shortness of breath. Remind them to contact you immediately if they develop any of these symptoms.
- Patients older than 35 years and who smoke should not take combination oral contraceptives at all, as they increase the risk of all serious cardiovascular events, including blood clots.
- Report any side effects to the FDA MedWatch program.
Jill Shuman, MS, ELS
Published October 31, 2011
References
- Combined Hormonal Contraceptives (CHCs) and the Risk of Cardiovascular Disease Endpoints. U.S. Food and Drug Administration (FDA). http://www.fda.gov/downloads/Drugs/DrugSafety/UCM277384.pdf. Updated October 28, 2011. Accessed October 28, 2011.
- Lidegaard O, Nielsen N, Skovlund CW, et al. Risk of venous thromboembolism from use of oral contraceptives containing progestogens and oestrogen doses: Danish cohort study, 2001-9. BMJ. 2011;343:d6423. doi:10.1136/bmj.d6423.
Recent Comments