Deep Vein Thrombosis in Pregnancy

Medically Reviewed by Melinda Ratini, MS, DO on October 04, 2022
4 min read

Deep vein thrombosis (DVT) happens when a blood clot forms in one or more of the veins deep in your body. These clots usually start in your legs, but they can also affect your pelvis or arms. DVT is not common, but pregnancy can increase your risk.

Blood clots are treatable and often preventable. With the right care, you can keep yourself and your baby safe.

When you’re pregnant, you’re five times more likely to get a blood clot than a woman who isn't expecting. That's because of how your body changes to prepare for the birth of your child. During pregnancy:

  • Your blood clots more easily so you'll lose less blood during childbirth.
  • Your growing baby presses on blood vessels around your pelvis, which reduces blood flow to your legs.

You're also at higher risk for DVT during childbirth, and for up to 3 months after you give birth.

After you deliver your baby, you often move around less as you rest and recover. This means less blood flow in your arms and legs, which raises your risk of blood clots.

Sometimes, you don't have any symptoms. But signs you might have DVT include:

  • Swelling
  • Pain (it might only happen when you walk or stand)
  • Veins that look larger than normal
  • Skin that’s red, discolored, or warm to the touch
  • Pain or tenderness that’s not caused by injury

Only about 1 pregnant woman out of every 1,000 gets a blood clot. But along with pregnancy, some other things increase your risk for DVT. Risk factors include:

Most of the time, your body breaks down a blood clot before it can cause serious problems. But when you’re pregnant, there’s a greater risk that the clot will grow larger and break off. It can then travel through your bloodstream and into your lungs. Doctors called this a pulmonary embolism (PE). It’s one of the most common causes of pregnancy-related deaths in the U.S. Blood clots can also cause:

Blood clots can also form in the placenta, the organ that supplies your baby with blood. This mostly happens in women who are already at higher risk of developing a blood clot. It can result in a miscarriage or stillbirth.

To help prevent blood clots during pregnancy, first be aware of the risk factors. Know whether you have a family history of blood clots or blood clotting disorders. And watch for any symptoms. To reduce your risks, also:

  • Avoid sitting still. If you have surgery or have been on bed rest, start slowly. But move around gently as soon as you can. Avoid crossing your legs, which hinders blood flow. When you travel long distances, stop often and walk around. If you’re on a plane, stand up and walk up and down the aisle occasionally. While sitting, exercise your legs. Raise and lower your toes while your heels stay on the floor. Then raise your heels, keeping your toes down.
  • Try raising and lowering your heels while keeping your toes on the floor, then raising your toes with your heels on the floor.
  • Make lifestyle changes. Quit smoking. Follow your doctor's advice on what and how much you should eat to avoid gaining too much weight. Get as much exercise as your doctor recommends.
  • Stay hydrated. Drink plenty of water.

If you have DVT, your doctor can help you manage it with a medicine that thins your blood. The main treatment for pregnant women is low molecular weight heparin, which you get as a shot. Your doctor will usually prescribe it to you for at least 3 months and until 6 weeks after you deliver. It won’t affect your placenta or breast milk.

Your doctor may also recommend that you wear compression stockings. These are tight-fitting socks you wear on your lower legs to help stop swelling from DVT.

You’ll need regular checkups to make sure the clot is gone and that no new ones have appeared. In the meantime, avoid sitting still for long periods, eat healthy, and exercise.