Blood Clots & Birth Control

Blood clots & birth control at a glance

  • Women who take birth control pills have a higher-than-average risk of developing blood clots, but that elevation of risk is small.
  • Recent studies indicate that the type of birth control pill affects the extent of the increased risk, with the newer combination pills (with ultra-low doses of estrogen) causing less of a risk.
  • The increased risk of blood clots from birth control pills is less than the increased risk of blood clots from being pregnant.
  • Despite the increased risk, the majority of women are able to use birth control pills and other hormone-based birth control methods safely without experiencing clotting.
  • Each woman should consult with her doctor to find which type of birth control is best for her.

How hormone-based birth control affects blood clots

Blood clots form when blood sticks together in a clump, restricting normal circulation. Blood clots occur for a variety of reasons, including the thickening of blood caused by the hormones in birth control pills.

Deep vein thrombosis (DVT) is the most dangerous type of blood clot. It forms in veins deep in the body, such as the thigh or hip. These clots may break off and can travel to the lungs, blocking the flow of blood. This is called a pulmonary embolism. People who experience DVT are more likely to have a stroke or a heart attack later in life.

While birth control pills have long been known to increase the risk of blood clots, more recent studies have shown that different types of birth control pills increase that risk more than others. The Food and Drug Administration (FDA) reports that women who use a newer generation of birth control pill that contains the manmade hormone drospirenone have a higher risk of blood clots than women who take birth control pills that contain the manmade hormone progestin.

Some studies showed that the increase in risk with drospirenone pills can be as much as threefold higher, while other studies showed no increase in risk at all. A new Danish study released after the FDA report found that the risk of blood clots was no greater with drospirenone pills than with other combination-form birth control pills.

The FDA recently required labeling on these drospirenone products that states that they carry a slightly higher risk for blood clots than other products. Products containing drospirenone are some of the most popular birth control pills available, and include such brand names as Yaz, Yasmin, Beyaz, Ocella and Zarah.

The FDA recommends that all women talk to their doctors about the risk of blood clots before deciding which birth control pills or form of birth control to use.

Should I use birth control pills if I have blood clots?

Some women are predisposed to blood clots for a variety of reasons and should avoid birth control pills. Because birth control pills can be a cause of blood clots, women who have blood clots or have experienced them in the past should check with their doctor before continuing, or beginning to take, birth control pills.

Women should discontinue use of birth control pills if:

  • Their blood clotting problem is not being successfully treated and they are taking the progestin-only type of birth control pill called the “mini” pill
  • They have certain types of inherited blood clotting disorders, such as Factor V Leiden mutation, and are taking the combination pill
  • They have had blood clots or vein inflammation and are taking the combination pill

Should I use other estrogen-based birth control devices if I have blood clots?

Not without consulting your physician. Birth control implants, patches, injections and vaginal rings that deliver estrogen to prevent conception may not be safe for a woman who has blood clots or is at high risk for having blood clots. Your physician will know whether these types of birth control are right for you.

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