Blood Clots, Birth Control and Being Aware


Whether it is arsenic in your apple juice, or blood clots from taking birth control pills, it is always disconcerting to hear that something you thought was safe may in fact be risky. The drospirenone clot issue first came to light in May 2011 when two studies suggested that drospirenone, one of the hormones in Yaz, Yasmine, BeYaz and generic equivalents, might increase the risk of a life-threatening venous thromboembolism, a clot that forms in blood vessels and then breaks off and travels to other parts of the circulatory system, potentially causing a stroke or heart attack. Many other studies did not show such an association, which is why the FDA decided to review all the data and determine if there was reason for concern.

An FDA committee met and decided that drospirenone may have a slight increase in risk over other pills, but the data was not conclusive enough to tell women to stop taking drospirenone products or to pull them off the market.

All hormonal contraceptives with estrogen will increase the risk of blood clots, particularly in women who are smokers or who are obese. Additional risk factors include a genetic predisposition to blood clots, recent surgery, cancer and/or prolonged immobilization. Fortunately, blood clots in young women are very rare, which is why knowing the actual numbers helps to keep things in perspective.

  • The likelihood of a blood clot if not on birth control pills is two to three for every 10,000 women
  • The likelihood of a blood clot when taking birth control pills is three to nine for every 10,000 women
  • The likelihood of a blood clot during pregnancy is 5-20 for every 10,000 women
  • The likelihood of a blood clot post partum is 40-65 for every 10,000 women

Clearly, anyone can develop a blood clot, but it is far more likely during pregnancy or after delivery than while taking contraception. Also, most clots occur in the first few months of pill use, so women who have been on pills for years are at significantly lower risk.

Ultimately, the FDA concluded that the benefits outweigh the risk and since the data is not conclusive, the FDA is not currently recommending that women stop taking drospirenone products. The only outcome of the meeting is that, in a move similar to the European counterpart to the FDA, product inserts will now reflect the concern.