Deep vein thrombosis (DVT) is a blood clot that forms in a vein inside a muscle. It usually happens in your legs, but you can also get them in your arms, chest, and other areas of your body.
It can be serious. It may make your leg hurt and swell. The clot might move and get stuck in a blood vessel in your lungs, brain, or heart. That could cause organ damage and even death -- within hours.
Obesity has more than doubled since 1980 worldwide. The number of deep-vein clots is rising right along with that.
Doctors aren't yet sure exactly why, but people who have a body mass index of at least 30 are more likely than people of normal weight to get a blood clot deep in a vein, called deep vein thrombosis, or DVT.
The main cause of DVT is poor blood flow. When it slows, blood can pool, which gives the cells a chance to stick together and start clotting. Someone whose blood clots easily is also at greater risk.
You're more likely to get a clot after any surgery that reduces blood flow to a part of your body or after major surgery on your legs, belly, or chest. That includes orthopedic surgery, such as a hip replacement, and abdominal surgery where you'll be under general anesthesia for more than 30 minutes.
The procedure could set tissue, protein, and fats loose in your veins. If the wall of a vein gets accidently damaged, it can release chemicals that trigger blood clotting.
Following major surgery, you'll probably be on bed rest. You won't be using your leg muscles, and that slows your blood flow.
Medical Conditions and Treatments
DVT can happen at any age, but being older than 60 makes it more likely.
Any illness that puts you in bed for more than 3 days can set you up for DVT. And if you've had circulation or clotting problems before, you could have them again.
These are some of the most common medical risk factors for DVT:
An injury that lessens blood flow, such as a broken pelvis, hip, or leg