Pregnancy Problems

Blood Clot During Pregnancy

The scoop on why you're more prone to dangerous blood clots during pregnancy, how to know if you could be at risk and what to do if you get one.

What is a blood clot?

A clot is formed by platelets in the blood clumping together to form a solid plug at the site of an injury, which reduces bleeding. Everyone’s blood is meant to clot (it’s how you keep from bleeding to death if you cut yourself while shaving). But during pregnancy, increased levels of estrogen means blood clots more readily. The clot itself isn’t necessarily the problem, it’s the location of the clot and what symptoms it may cause.

What are the signs of a blood clot?

In pregnant women, one of the primary areas for blood clots to form is in the deep veins of the legs. This is known as deep vein thrombosis, or DVT. You’ll notice this if one leg is more unusually swollen than the other. Other common symptoms include a pain behind the knee of a leg that feels warm to the touch. In other areas, you may feel pain due to a loss of oxygen to the region.

Are there any tests to determine if I have a blood clot?

In many cases, your doctor can look at the affected area through an ultrasound scan; if the blood clot is in the lungs, he can perform a spiral CT scan.

How did I get a blood clot?

All pregnant women are at risk, since estrogen levels naturally rise during pregnancy, but those who are put on bed rest, take a long flight or car trip, are obese, or have a genetic tendency to develop clots are all at higher risk.

How will my blood clot affect me and my baby?

The biggest danger of a blood clot is the risk that it can break off from its location and travel to the lungs, causing a potentially fatal condition called pulmonary embolism. Blood clots can also be dangerous to your baby — if they form inside the placenta, they may cut off blood flow to the fetus (see next page for treatment and prevention tips).

What’s the best way to treat a blood clot?

If you develop a blood clot during pregnancy, you’ll likely be given a medication that’s an anticoagulant, that is, it helps prevent the blood from clotting. Warm compresses can also help to treat a clot that’s close to the skin’s surface.

What can I do to prevent a blood clot from forming?

If you’re taking a long trip (more than few hours), get up every 20 minutes or so and move about (you’ll probably be hitting the bathroom about that often anyway, depending on how late into the pregnancy you’re going). Cut down on the amount of salt in your diet, which can cause swelling, and try not to cross your legs for long periods of time. If you’re stuck home on bed rest, don’t use pillows under your knees and ask your doctor if there are any exercises you can do to cut down on your risk.

What do other pregnant moms do when they have blood clots?

“I’m pregnant through IUI and have some blood clotting issues in my uterus. My perinatal doctor put me on Lovenox and baby aspirin and doesn’t seem too concerned. I had some severe bleeding around week 12.”

“I had a blood clot in my uterus. I bled around week 7, but baby was fine. The doctor put me on a ton of prescription folic acid and a baby aspirin per day. As of now, the clot is shrinking and barely noticeable.”

“I was diagnosed last week with multiple blood clots in superficial veins. Without testing to see whether I might have a blood clotting disorder, the on-call OB wants me to take a baby aspirin daily until 20 weeks.”

Are there any other resources for blood clots?

National Blood Clot Alliance

By Robert Wool, board-certified ob-gyn at Women’s Health Associates in Westfield, MA