context: While men generally are more likely to have deep vein thrombosis, hormones during different stages of women's lives can raise their chances of getting a potentially deadly clot. The blood's ability to clot is often a good thing: It's how you stop bleeding after you get a bad scrape or cut. But a blood clot deep inside a vein in your leg or pelvis (a condition known as deep vein thrombosis, or DVT) can damage the tissue around it. Or, if the clot moves to a lung, it can stop oxygen from getting to the rest of your body. Women who are pregnant or use certain methods of birth control or hormone replacement therapy ( HRT) for menopause may not realize they're at higher risk for DVT. While you're expecting a baby, and up to 6 weeks after you deliver, your chances of DVT are four to five times greater because of hormonal and physical changes in your body. Blood flow slows down, making it more likely to pool and clot. Your expanding uterus can press on veins, making it harder for blood to get through. It also gets more difficult for you to move and stay active. All of these increase your risk for DVT. Your doctor may prescribe a medicine that prevents blood clots from forming if: You have a blood clotting disorder or had a clot before. Your doctor puts you on bed rest. You're planning a C-section. Heparin is an anticoagulant drug that's safe and often used during pregnancy. If you don't take a blood-thinner medication, your doctor may want you to use a device that gently squeezes your legs to keep blood flowing. Even if you don't have other risk factors, be aware, especially when you're traveling. Symptoms of DVT can include pain in your ankle, calf, or thigh when you stand or walk, or a sudden swelling, warmth, or redness in your skin. See a doctor right away if these happen. Take precautions. When you'll be mostly still for several hours -- like on a long trip by plane, train, or car, or on bed rest -- drink lots of fluids, wear loose-fitting clothing, and try to walk around or at least stretch and move your legs every hour or so. Ask your doctor about compression stockings to help keep blood from clotting in your legs. Three kinds of birth control have estrogen: combination pills, the patch, and the ring. While these methods are considered safe for most women, they do increase the likelihood of DVT. Combination birth control pills could more than triple your risk, though the risk overall is still small. But this boost might be enough to lead to a clot in some situations -- a flight across an ocean and back, for example -- even if you're young and otherwise in good shape. Some aspects of your health can make this type of birth control more dangerous. Talk to your doctor about estrogen-free methods, such as progestin-only birth control pills, an IUD, the shot, or the implant if you're: Significantly overweight Smoke more than 15 cigarettes a day and are older than 35 Have high cholesterol or high blood pressure Some older women take estrogen therapy (or a combination of estrogen and progestin) to help relieve symptoms of menopause. This can also lead to DVT. Your chances go up as you get older. Other things that sometimes come with aging don't help either: Obesity Moving less Heart disease Bone fractures Your risk of blood clots may be lower when you get estrogen absorbed through skin patches rather than taking it in pills. Talk to your doctor about whether the benefits of HRT outweigh the possibility of a deep-vein clot, and ask which method is safest for you.