Surgery, pregnancy, obesity — a number of factors can increase your risk of deep vein thrombosis (DVT), a blood clot that forms in a deep vein. The largest risk factor: Having experienced a previous episode of DVT.

The chances of having a second DVT or pulmonary embolism, in which a blood clot travels to the lungs, are about 11 percent after the first year and about 40 percent after 10 years, according to research published in a 2007 issue of Haematologica. Other studies have put recurrent risk of DVT at around 11 to 15 percent within one year. Your personal risk depends on factors such as the cause of your first DVT, how long ago you had it, and other factors, like having cancer.

But there are also a number of changes you can make in your life to reduce your chances.

DVT Risk Factors

DVT stems from a number of different causes. The National Heart, Lung, and Blood Institute explains that blood clots may form because of damage to the lining of a vein or tissue, because your blood is thicker than normal, or because your blood isn’t moving as quickly as it should.

Whether it’s the first instance or recurrent DVT, risks for DVT include a genetic risk for clotting, hormone use or pregnancy, surgery, injury to the vein, cancer, and periods of immobility, says vascular surgeon Luigi Pascarella, MD, assistant professor of surgery in the division of vascular surgery at the University of Iowa Hospitals and Clinics in Iowa City.

Medication and Stockings for DVT

If you have had DVT, your doctor may prescribe medication to help prevent a recurrence. Some people will be able to stop taking that medication with a doctor’s permission about three months after their episode and take it again only during periods of high risk, such as surgery, according to clinical practice guidelines published in Chest in 2012. Others may need to take blood-thinning, or anticoagulation, medication for a longer time to prevent DVT.

Your doctor might also recommend compression stockings, which lightly squeeze the legs and help blood flow.

“A patient with history of recurrent DVT is recommended for lifetime systemic anticoagulation and compression stockings,” Dr. Pascarella says. “While compression stockings do not prevent recurrence of DVT, they do reduce the risk of post-thrombotic syndrome [vein damage resulting in pain, swelling, and hyperpigmentation] and the development and recurrence of venous ulcers.”

Your doctor could also recommend additional testing to determine whether you have an underlying condition that increases your DVT risk. If you do, your treatment plan will also need to address this condition.

7 Ways to Reduce Recurrent DVT Risk

Follow these steps to reduce your risk of having another DVT: