Yaz and Yasmin: the Facts Behind the Hype

The New York Times reported September 25 on the controversy surrounding Yaz and Yasmin, two popular birth control pills (BCPs). Part of the controversy stems from problematic marketing and manufacturing processes identified by the Food and Drug Administration. However, the principal concern is whether these medications increase the risk of blood clots.

To understand the safety issues, here’s a little background. Common estimates are that at baseline about 1 women in 10,000 will have a blood clot this year; that number increases to about 3 women in 10,000 if they’re taking BCPs. (Compare this to the fact that more than 50 women in 10,000 will get a blood clot due to pregnancy.) Since this is true for many BCPs, what’s so special about Yaz and Yasmin?

Like many BCPs, Yaz and Yasmin use both estrogens and progestins to prevent ovulation. However, unlike other BCPs, Yaz and Yasmin use a new progestin called drospirenone. The research on drospirenone is contradictory: one study sponsored by the manufacturer found no increased risk in blood clots, while two studies by independent researchers found a slight increase in blood clots from drospirenone.

Let’s take a closer look at these studies that show an increased risk. A Danish study by Lidegaard, published in the British Medical Journal, examined women taking different types of oral contraceptives. As expected, they found that the pill increases the risk of blood clots, from an annual rate of 3 per 10,000 women to 6 per 10,000 women. What did they find specifically about drospirenone? Comparing drospirenone to levonorgestrel (a progestin found in other BCPs such as Alesse and Nordette), they found that annually, 5.5 women out of 10,000 on levonorgestrel BCPs had blood clots, while about 8 women out of 10,000 on drospirenone had blood clots. A similar increase was also found when other progestins (desogestrel and gestodene, found in OrthoCept, Mircette, and others) were compared to levonorgestrel.

The second study, done in the Netherlands by van Hylckama Vlieg, found similar results. Patients taking BCPs had higher rates of blood clots: in patients aged 30-40 years old, the annual rate of blood clots was 2 per 10,000 women in patients who didn’t use BCPs, and 10 per 10,000 women who did use BCPs. It was lower in women younger than 30 and slightly higher in women older than 40. While the authors don’t report their results in the same manner as the previous study, extrapolation from their data shows that drospirenone has an annual rate of 12 blood clots per 10,000 women aged 30-40. Desogestrel BCPs also had similar increased rates compared to baseline.

The bottom line from these studies: Yaz and Yasmin, which use drospirenone, have a slightly higher risk of blood clots than BCPs using levonorgestrel. This risk is not dramatically higher. Furthermore, other BCPs containing desogestrel and gestodene also have a slightly increased risk of blood clots compared to levonorgestrel.

If you’re weighing the risks and benefits of birth control, remember that BCPs decrease the risk of getting ovarian and endometrial cancer. Also they definitely decrease the medical risks associated with pregnancy! To counter those benefits, there are some risks in smokers–people who smoke face increased risks of breast cancer and heart attacks if they use BCPs. There is debate whether non-smokers have an increased risk of breast cancer and heart attacks while using BCPs, currently there is no consensus on these issues.

So what should you do if you’re on Yaz or Yasmin? There’s no immediate cause for serious worry, but please use the information in this post to have an informed conversation with your health care provider about the best option for your individual situation. There might be a levonorgestrel-based BCP that’s better for you.

Gregg Miller, MD is a board-certified emergency room physician. Not nearly as good-looking as the doctors on the TV show  ER,  lacking the charisma of Dr. House, and much less scandalous than anyone o ...read more


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