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Yaz Blood Clots

The formation of blood clots can be a potentially dangerous condition that may lead to life-threatening complications. While there is no way to completely eliminate the risk of a blood clot forming, there are some factors that actually increase that risk. Those factors include some medications, particularly those marketed as oral contraceptives to prevent pregnancy, such as blockbuster drugs Yaz & Yasmin.

Oral contraceptives typically feature a mix of the female hormones estrogen and progestin. While a combination of these hormones can increase the risk of blood clot formation in users, there are some types of progestin that have been linked to a higher risk than others. Fourth-generation synthetic progestins like drospirenone fall into this higher-risk category.

Drospirenone is found in the oral contraceptives Yaz and Yasmin, manufactured and marketed by Bayer. Concern over Yaz and Yasmin blood clots has been reported for some time, as more women have come forward after suffering injuries linked to the drugs. Some have filed lawsuits against the pharmaceutical giant, claiming Bayer did not provide sufficient warning about the potential risks associated with their products.

Yaz and blood clots

Blood clots can form in various areas of the body, although the most common location is a deep vessel in the leg – a condition known as deep vein thrombosis or DVT. While they may not present with any visible symptoms, if the clots break free from their original location and begin traveling through the bloodstream, they can cause life-threatening injuries.

Blood clots can lead to these complications:

  • Stroke – if blood clot travels to the brain
  • Heart Attack – if blood clot lodges in a vessel of the heart
  • Pulmonary Embolism – if clot blocks an artery in the lung

Both estrogen and progestin play a role in increasing the blood clot risk. Estrogen increases production of certain chemicals that contribute to the body’s clotting action. Progestin relaxes blood vessels, allowing them to widen and increasing the likelihood of a clot forming.

Drospirenone has been shown in some studies to carry a higher risk of blood clot formation than other types of progestin used in oral contraceptives.

Some factors increase the risk of Yaz or Yasmin blood clots even more:

  • Over the age of 35
  • Smoker
  • Overweight
  • Previous history of venous conditions
  • Family history of blood clotting conditions
  • Personal history of migraine headaches
  • Heart conditions that can lead to blood clots

Women who have one or more of these risk factors should talk to their doctors about the dangers of Yaz and Yasmin blood clots to determine if another oral contraceptive might be a safer choice.

Studies on Yaz blood clot risks

Since Yaz and Yasmin were approved by the FDA in 2001 and 2006, respectively, reports of adverse events have concerned healthcare providers and other medical professionals. Various countries including the U.S. have conducted studies on the risk of blood clot formation in women using an oral contraceptive containing drospirenone.

Studies on the link between oral contraceptives and blood clots:

  • A study published in the British Medical Journal in April 2011 found that oral contraceptives containing drospirenone led to a higher incidence of venous thromboembolism (blood clot) than drugs containing levonorgestrel.
  • A review by Health Canada published in December 2011 found that the risk of blood clots was 1.5 to three times higher with women using an oral contraceptive containing drospirenone. The agency used numerous observational studies to base its safety warning.
  • In April 2012, the FDA reported findings from its review of a series of observational studies as well. Based on the review, the agency determined oral contraceptives containing drospirenone carried a higher risk of blood clot formation than other types of birth control pills.
  • Kaiser Permanente released results from its own study in October 2012 that showed women who took oral contraceptives containing drospirenone had a 77 percent higher chance of being hospitalized for a venous thromboembolitic event and a 50 percent higher risk of hospitalization for an arterial thrombotic event.

FDA takes action

Since it approved Yaz and Yasmin, the FDA has been active in warning the medical community and general public about Yaz blood clot risks as the agency has learned of such risks.

FDA warnings about Yaz & Yasmin from the agency have included:

  • April 2010: The FDA updated the warning label for Yaz and Yasmin to alert users of the possibility of vascular issues and blood clot formation related to the oral contraceptives.
  • May 2011: Two new studies were reported by the FDA that showed women who used drospirenone-containing oral contraceptives has a higher risk for blood clot formation.
  • October 2011: The FDA released initial findings from an observational study that linked drospirenone to a 1.5 percent higher risk for blood clot formation.
  • April 2012: The FDA once again updated the warning label for Yaz and Yasmin, alerting consumers and physicians to the higher risk of blood clot formation.

Yaz and Yasmin blood clot litigation

Some women who have developed Yaz and Yasmin side effects have taken their cases to court in pursuit of legal compensation for their injuries. Many of those complaints have now been coordinated into multidistrict litigation in U.S. District Court for the Southern District of Illinois. An MDL may be established when a growing number of plaintiffs file similar complaints against the same defendants, in order to simplify early trial proceedings.

In April 2014, Bayer agreed to settle more than 8,000 cases involving women who alleged they suffered a blood clot injury after taking the oral contraceptive. Hundreds of cases are still pending in court and may be going to trial if further settlement negotiations are not reached. In the meantime, women continue to come forward, filing Yaz lawsuits against Bayer to compensate them for pain and suffering, medical bills and lost wages as they sought treatment for their injuries.

  1. FDA, FDA Drug Safety Communication: Updated Information about the Risk of Blood Clots in Women Taking Birth Control Pills Containing Drospirenone,
  2. U.S. District Court, Southern District of Illinois, MDL No. 2100,
  3. Science Daily, Elevated Risk of Blood Clots in Women Taking Birth Control Containing Drospirenone,
  4. Medical News Today, Contraceptives Containing Drospirenone Have Higher Blood Clot Risk,
  5. Government of Canada, Yasmin and Yaz (Drospirenone): Updated Information on Increased Risk of Blood Clots,
  6. British Medical Journal, Risk of Venous Thromboembolism in Users of Oral Contraceptives Containing Drospirenone or Levonorgestrel: Nested Case-Control Study Based on UK General Practice Research Database,