Blog of the Society for Menstrual Cycle Research

Yaz, Yasmin and Ortho Evra patch increase risk of blood clots

December 14th, 2011 by Laura Wershler

Blood clots are a serious, if rare, side-effect of hormonal contraceptives. If left untreated, clots can lead to debilitating, or fatal, strokes. The increased risk of blood clots in users of some hormonal birth control brands has been the subject of several recent news stories.

In early December, Health Canada asked Bayer Inc. to change the labels on Yaz and Yasmin, two of the most popular birth control pills, because use of the drugs is linked to higher rates of blood clots.

According to a November 2011 story at, health problems associated with these two drugs include stroke, deep vein thrombosis, pulmonary embolism and heart attack.

The concern surrounds the progestin – drospirenone –  used in Yaz and Yasmin. Although promoted as being associated with less bloating and clearer skin than other progestins, drospirenone is also associated with a “1.5-to-three fold increased risk of experiencing a clot compared to women using other birth control drugs.

What this means in real terms varies from study to study, but one study led by Susan Jick of Boston University found the rate of non-fatal blood clots to be 30.8 per 100,000 among women taking Yaz or Yasmin (the only drugs containing drospirenone) compared to 12.5 per 100,00 among those taking pills containing the older, more common progestin levonorgestrel.

In related news this past week, advisers to the FDA recommended that Johnson and Johnson revise the label on its Ortho Evra birth control patch to better explain the risk of blood clots. Use of the patch has been associated with a higher rate of blood clots for several years. Publicity about the clot risk has no doubt contributed to a 50% decline in sales in the last five years. The formulary problem with the patch is its higher dose of estrogen compared to other pills.

The FDA advisers also recommended more detailed description of blood clot risks for Yaz and Yasmin.

What caught my eye in both stories were the take home messages from those requiring these label changes to women using these drugs.

Health Canada said women should talk with their doctors about the risks and benefits of taking drospirenone-containing oral contraceptives but did not urge women to stop using Yaz and Yasmin.

The FDA’s reproductive health advisers “voted 19-5 that the benefits of the weekly Ortho Evra patch outweigh its risks, including a potentially higher risk of dangerous blood clots that can cause heart attack, stroke and other life-threatening problems.”

I want to know why the five FDA panelists opposed to this decision think the benefits of the patch DO NOT outweigh the risks.

These news stories beg the question:  Should women be concerned enough about the increased blood clot risk associated with Yaz, Yasmin and the Ortho Evra patch to stop using these brands?  If you take these drugs, are you concerned?

If adverse publicity about blood clots resulted in a sharp decline in sales of the Ortho Evra patch, we should expect to see a similar decline in sales of Yaz and Yasmin.

The article reports that the family of a Toronto woman, who died of a large pulmonary embolism after taking Yasmin, has filed the first individual civil suit against Bayer Inc. in Canada. It also states that “more than 10,400 individual lawsuits related to the two pills have been filed in the U.S.”  Not to mention the class action suits related to these drugs currently in progress in both countries.

One thing is certain, the litany of stories about the adverse effects of hormonal contraceptives is not about to end anytime soon. Stay tuned.

4 responses to “Yaz, Yasmin and Ortho Evra patch increase risk of blood clots”

  1. Laura,
    I share your concerns about these contraceptive methods.
    But there is some missing information and physiology here that all women need to know.
    1) It is the estrogen and not the progestin in the Yaz and Yazmen that is causing the problems with clots.
    We have known since the late 1960s that high dose ORAL estrogens cause venous thromboembolism (blood clots, strokes, pulmonary emboli and heart attacks). Ironically, Yaz and Yazmen have the lowest estrogen doses currently available.
    So–what’s going on?
    In the early days of The Pill, the progestins used were very strong and derived from male hormone precursors (such as Levonorgestrel or Norethindrone). These strong progestins counteracted estrogen’s ability to increase liver proteins especially those related to increasing clotting. A marker of that effect to prevent estrogen’s clotting effects if measurement of Sex Hormone Binding Globulin (SHBG for short). SHBG levels rise a lot with the newer progestins, especially drosperinone or cyproterone acetate (in Diane-35), and rise very little with Levonorgestrel-containing pills (such as Alesse).

    The other issue, since Yaz and Yazmen are lower dose estrogens, is that physicians chose to use them with women with higher blood clots risks. This further confuses the issue.

    All I know is that a huge long-term trial post-marketting surveillance in Europe showed no greater incidence of blood clots in women using drosperinone-containing than oral contraceptives with other progestins. Not clear why the difference in data.

    So let’s put the blame where blot clot blame belongs–on the estrogen.

    2) Transdermal or vaginal (as in the NuvaRing) forms of estrogen SHOULD have lower risks for blood clots than oral forms because the estrogen in them does not go into the stomach and through the liver to raise those bad clotting factors. However, when Ortho formulated Evra for the USA they put too high a dose of estrogen in it. In Canada, the estrogen dose is significantly reduced.

    Hope these ideas clarify some of the confusion about why seemingly improved and “good” contraceptive agents turn out to more frequently do bad things like stimulate blood clots.


  2. Laura Wershler says:


    Thanks for this additional information. Sounds like the real take away message is that physicians should not be prescribing Yaz and Yasmin on the basis of its lower estrogen content. Also, I believe increased Sex Hormone Binding Globulin is associated with lowered libido. This makes two big reasons why Yaz and Yasmin might not be the best oral contraceptive choice for women’s health and well-being.

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