DVT and Birth Control Pills (Oral Contraceptives)

Birth control pills (oral contraceptives) can slightly increase the risk of developing blood clots, including DVT.

A blood clot in a deep vein is called a venous thromboembolism (VTE). Deep vein thrombosis (DVT) is the most common type of VTE, and it refers to blood clots that form in the deep veins of the thigh, lower leg, pelvis, or arm. When clots form in these deep veins, blood can back up, causing swelling and pain.

DVT can be dangerous because if the blood clot breaks off, it can travel through the bloodstream and block blood vessels in other parts of the body. Pulmonary embolism (PE) is a condition that can be fatal and occurs when blood clots break off from the legs or pelvis and travel to the lungs.

Birth control pills can slightly increase the risk of developing blood clots, including DVT. However, the increased risk of blood clots from birth control pills is less than the risk of blood clots associated with pregnancy.

The risk of developing a blood clot is highest in the first year of oral contraceptive pill (OCP) use. The risk decreases after the first year but remains until the pills are stopped.

If you have had blood clots in the past or have risk factors for blood clots, check with your doctor before taking any birth control pills.

Risk factors for blood clots include:

• Smoking
• Obesity
• Genetic blood clotting disorders such as Factor V Leiden mutation
• Previous history of blood clots
• Family history of blood clots
• Age over 40

Other medical conditions that increase the risk of blood clots include:

• Heart disease
• Lung disease
• Inflammatory bowel disease or IBD (Crohn's disease and ulcerative colitis)
• Recent childbirth
• Being on bed rest or sitting for long periods

• Implant: etonogestrel implant (Nexplanon)
• Intrauterine devices (IUDs): Paragard, Mirena, Skyla, and Liletta
• Contraceptive shots: medroxyprogesterone acetate (Depo-Provera)
• Progestin-only birth control pills
• Condoms
• Diaphragms

Emergency contraception such as Plan B (or the morning-after pill) is not meant to be used as birth control, but it also does not contain estrogen and does not increase the risk of blood clots and DVT.

If a clot is small, there may be no symptoms of DVT.

Typical symptoms are related to the backup of blood in the leg and include:

• Swelling
• Pain or tenderness in the thigh, calf, or foot
• Redness
• Warmth
• Veins in the affected leg may appear larger than normal
• Leg cramps, especially at night
• Bluish or whitish discoloration of skin

If DVT is not treated, it can cause complications including pulmonary embolism (PE) and post-thrombotic syndrome.

If a blood clot breaks off and travels to the lungs, it can block blood vessels, causing a pulmonary embolism, which can be fatal. A blood clot in the lung (pulmonary embolism) is a medical emergency. If you have any symptoms of DVT seek medical treatment immediately.

The later signs and symptoms of a blood clot in the lung include:

• Shortness of breath
• Chest pain, worse with coughing or moving
• Cough, may be bloody or contain phlegm
• Back pain
• Increased sweating
• Lightheadedness or fainting
• Rapid heartbeat
• Blue lips or nails (cyanosis)

Another complication of DVT is post-thrombotic syndrome, which affects the tissues in the calf and can cause long-term symptoms including:

• Calf pain
• Dilated blood vessels in the leg
• Swelling
• Rash
• Skin discoloration
• Ulcers on the calf (in severe cases)

Serious and even fatal complications such as pulmonary embolism can arise from untreated blood clots. If you think you may have symptoms of a blood clot, see your doctor right away.