An Overview of Birth Control and the Risk for Blood Clots

Hormonal birth control increases the risk of blood clots in some people with a uterus. The estrogen in combination hormonal birth control methods adds to the risk of a blood clot in the leg, a condition known as deep vein thrombosis. Combination hormonal birth control pills that contain certain types of progestin also increase the risk of blood clots more than birth control pills that contain other types of progestin.

In this article, we'll look into the connection between blood clots and hormonal birth control, as well as the signs and symptoms of a blood clot and how to reduce your overall risk.

woman looking at birth control pack

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What Is a Blood Clot?

A blood clot, also known as a thrombus, is coagulated, or clotted, blood. Blood clotting isn't always a cause for concern. However, it becomes a problem when the clot blocks blood flow within certain arteries or veins, such as those that deliver blood to the heart, lungs, or brain. These blood clots are considered an emergency and require immediate medical attention.

There are different kinds of blood clots. Deep vein thrombosis (DVT) affects the legs, while pulmonary embolism (PE) blocks the arteries in the lungs. A blood clot in a leg vein can migrate to the lungs and cause PE. Stroke can be another type of blood clot, and it affects the brain.

The Connection to Hormones

Hormonal birth control is linked to blood clots primarily because of estrogen, an ingredient in many combination hormonal birth control methods. However, the risk of DVT or PE is overall very low with hormonal birth control. Combination birth control pills contained a higher dose of estrogen in the past. Now these pills contain a lower dose of estrogen, and the risk is reduced.

The risk of DVT or PE is higher for a pregnant woman than for a nonpregnant woman taking hormonal contraceptives.

The birth control patch delivers more estrogen than do low-dose birth control pills. The Food and Drug Administration (FDA) warns that women using the patch are slightly more likely to get dangerous blood clots in the legs and lungs than women using pills.

Combination hormonal birth control pills that contain the progestin called desogestrel may increase the risk of blood clots more than birth control pills that contain other types of progestin. The progestin called drospirenone (found in pills such as YAZ or Yasmin) may also lead to a greater risk of blood clots than other types of progestin.

The lowest-risk hormonal options are progesterone-only forms of birth control, such as the hormonal IUD. Data suggest that using progestin-only forms, such as the progestin IUD or progestin-only pills, does not raise the risk of blood clots.

Risk Factors

The known risk factors for blood clots include:

  • Pregnancy and the first six weeks after delivery
  • Personal or family history of blood clots
  • Obesity
  • Surgery (birth control pills are usually stopped within one month of major surgery to decrease the risk of a blood clot)
  • Coagulation disorders, such as factor V Leiden mutation, a genetic blood clotting disorder
  • Inactivity, such as during long-distance travel in cars or airplanes
  • Smoking

Signs and Symptoms of a Clot

Blood clot symptoms depend on where the clot is located and how big the clot is. There are certain scenarios in which a blood clot will not cause any symptoms. However, blood clots in major veins or arteries are almost always symptomatic, and require immediate medical attention.

While blood clots caused by birth control are rare, it is still important for those who are taking birth control to be aware of these signs.

For DVT, symptoms may include:

  • Swelling of the leg or arm (sometimes suddenly)
  • Pain or tenderness in the leg (may happen only when standing or walking)
  • Warmth in the area of the leg or arm that is swollen or hurts
  • Skin that is red or discolored
  • Larger-than-normal veins near the skin’s surface

For PE, symptoms may include:

  • Sudden shortness of breath or fast breathing
  • Sharp chest pain that often comes with coughing or movement
  • Pain in the back
  • Cough (sometimes with bloody sputum or phlegm)
  • Sweating more than normal
  • Fast heartbeat
  • Feeling dizzy or fainting

For stroke, symptoms may include:

  • Sudden or severe headache
  • Unexplained sudden numbness or weakness in an arm or a leg
  • Sudden visual changes
  • Slurring of speech

Recap

Blood clot symptoms vary based on the location and size of the clot. Both DVT and PE are serious medical conditions and require immediate care.

When to Seek Professional Treatment

If you suspect you may have DVT or PE, you should seek professional treatment for proper diagnosis and care. However, if you begin experiencing chest pain or shortness of breath, you should call 911 or go to the emergency room.

Additionally, if you're found to have blood clots as a result of hormonal birth control, you should work with your doctor to decide whether you should continue using hormonal birth control once the clot is treated.

Blood Clots Doctor Discussion Guide

Doctor Discussion Guide Old Man

People with a family history of blood clots or known blood clotting disorder are advised to also discuss the use of hormonal contraceptives with a specialist to make sure it is safe to do so since these are risk factors of developing blood clots.

Ways to Reduce Your Blood Clot Risk

Educating yourself on the signs and symptoms of a blood clot is the first step toward lowering your risk of complications or death.

If you are at increased risk of developing a blood clot, be sure to:

  • Exercise your lower leg muscles if you need to sit still for a long time. Stand up and walk at least every half hour if you are on a long flight, or get out of the car every hour if you are on a long road trip.
  • Take medications or use compression stockings after surgery (if prescribed by your doctor) to reduce your risk of a clot.
  • Follow up with your doctor and follow your doctor’s recommendations to reduce your risk of a clot.
  • Quit smoking cigarettes if you smoke.

Summary

Combination hormonal birth control can increase your risk of blood clots, including deep vein thrombosis (blood clots in your leg) and pulmonary embolism (blood clots in your lungs). Those containing estrogen are more likely to increase this risk. Certain types of progestin like desogestrel and drospirenone can also increase your chances of developing blood clots. The risk of DVT and PE is higher in pregnant people than in those who are not pregnant and are using hormonal birth control.

A Word From Verywell

The risk of blood clots due to using hormonal birth control is quite low. If you ever experience symptoms of a blood clot, you should call your doctor to be evaluated. Blood clots are treatable. If you experience symptoms such as shortness of breath or chest pain, you should visit the emergency room immediately. If you are concerned about beginning or continuing hormonal birth control, especially during pregnancy, talk to your doctor about the risks involved and ask any questions you may have.

Frequently Asked Questions

  • Does taking birth control while smoking increase your risk for blood clots?

    Yes, birth control and smoking can increase your risk for blood clots. Nicotine, the main toxin found in cigarettes, is known to raise blood pressure and heart rate. Combining cigarette use with taking combination hormonal birth control that contains estrogen increases your overall risk of blood clots, stroke, and heart attack.

  • How can you tell if your birth control gave you a blood clot?

    Most often, blood clots will start in the legs. Symptoms may include swelling in your legs, pain, tenderness, or warmth in the affected area, skin redness, and large veins that are visible on the skin's surface.

  • How quickly can birth control give you blood clots?

    The chance of developing blood clots is greatest when you just started taking the pill. This is usually within the first several months, though it could be within the first year. The reason for this is because this is when your hormone levels will go through the biggest change.

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3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Michigan Medicine. Hormonal birth control: Risk of blood clots. Updated October 8, 2020.

  2. Mantha S, Karp R, Raghavan V, Terrin N, Bauer KA, Zwicker JI. Assessing the risk of venous thromboembolic events in women taking progestin-only contraception: a meta-analysis. BMJ. 2012 Aug 7;345:e4944. doi:10.1136/bmj.e4944

  3. Cleveland Clinic. Deep vein thrombosis. Updated July 18, 2019.