So, although hormonal birth control with the CHC feature increases the risk of blood clots, the risk is only slightly higher than the risk for women who don't use CHCs, and is significantly lower than the risk faced by pregnant women. Some personal characteristics and medical conditions increase the risk of blood clots, including (but not limited to):

• obesity
• genetic clotting disorders
• smoking
• being over age 60
• prolonged inactivity (such as during long car or airplane rides)
• surgery
• cancer

Individuals with characteristics that increase their risk of blood clots should discuss the risks of using CHCs with their health care provider and/or pharmacist.

Estrogen increases blood's ability to clot. Taking estrogen-containing CHCs increases the body’s estrogen levels and therefore increases the risk of a blood clot.

Some studies suggest that the progestin hormones drospirenone and desogestrel may also increase the blood’s ability to clot. These newer-generation progestins are used in CHCs including Yaz, Yasmin, and Desogen.

Research indicates that the patch and vaginal ring have a higher risk of blood clots than most oral contraceptive pills. One study found that women using the vaginal ring were 1.9 times more likely to experience a blood clot than those taking combination birth control pills. In this study, women using the patch were 2.3 times more likely to experience a blood clot than those taking combination birth control pills. (The research compared the patch and vaginal ring to levonorgestrel-containing combined oral contraception.)

In 2011, the NWHN recommended that the Food and Drug Administration (FDA) reverse its approval of drospirenone pills (including Yaz, Yasmin, and Desogen) due to the method’s heightened risk of blood clots and lack of unique benefits over other contraceptive options. There are specific concerns about the health risks of Yasmin, which is manufactured by Bayer. The FDA has reprimanded Bayer for its misleading ads that overstated the pills’ benefits and downplayed risks, and for delaying reports about blood clots to the FDA during the approval process.

In 2012, the FDA reviewed studies on drospirenone-containing birth control and found the method may be associated with an increased risk of clots compared to other progestin-containing contraception. The FDA did not conclude there was a causal relationship, however. The science behind the risk of blood clots with these progestins is still emerging.

There are other contraceptive options that are preferable for people who are at increased risk of clots. In fact, the most effective contraception methods do not contain estrogen and are not associated with a higher blood clot risk. These include the arm implant (i.e., Nexplanon) and intrauterine devices (IUDs), such as ParaGard, Kyleena, Mirena, Skyla, and Liletta. Each of these methods has its own unique benefits and risks that potential users should consider.

In addition, Depo Provera, progestin-only pills, condoms, and diaphragms are all also estrogen-free, and safe for people with a high blood clot risk. Emergency contraception (such as Plan B, One-Step, and Take Action) does not contain estrogen, so it does not increase blood clot risks.

Yes. In addition to preventing unintended pregnancy, CHCs may reduce the risk of developing ovarian and endometrial cancer, heart disease, and ectopic pregnancy (a pregnancy occurring outside the uterus). CHCs can also reduce menstrual pain and heavy bleeding, facial hair growth, acne, and symptoms associated with premenstrual syndrome (PMS) and polycystic ovarian syndrome (PCOS).

CHCs carry very little risk for most people. In fact, CHCs are one of the most-studied and safest medications available today. The pill, patch, and vaginal ring each meets a unique need, and their availability is important in order to ensure that women can access a broad range of methods that suit their specific circumstances.

While the patch and vaginal ring both expose users to higher doses of hormones than pills, people may find the benefits of not having to take a pill every day to be worth the small increased risk. (However, as noted above, the NWHN believes that drospirenone should be taken off the market because the increased risk is not outweighed by an increased benefit.)

All contraceptive users need complete information about the risks and benefits of each potential method, so they can determine what method (or combination of methods) is best for them. If you are concerned about the increased risk of blood clots and other potential risks and benefits of various hormonal birth control options, talk with a qualified health care provider and/or pharmacist.