Yes. Some birth control pills can increase the chance of deep vein thrombosis (DVT), a blood clot in a deep vein, usually in the leg. The risk mainly applies to combined pills that contain estrogen and progestin; it remains small for most users. Pills without estrogen generally have a different risk profile. Your personal risk depends on factors such as clot history, smoking, surgery, and recent childbirth.
Which birth control pills can increase DVT risk?
Combined oral contraceptive pills contain two hormones: estrogen and a progestin. These pills can increase the risk of developing a blood clot in a deep vein. DVT most often occurs in the leg, thigh, or pelvis. If part of a clot breaks free and travels to the lungs, it can cause a pulmonary embolism (PE), a potentially life-threatening complication.
The risk is small, but it is important to understand. According to the NHS, blood clots affect up to 1 in 1,000 people using combined hormonal contraception, including the combined pill. This is a general estimate, not a prediction of an individual's risk. The likelihood can differ depending on the contraceptive formulation and the person's medical history.
Does the type of pill make a difference?
Yes. The main distinction is whether the pill contains estrogen.
Combined oral contraceptive pills
These contain estrogen and a progestin. Estrogen-containing contraception is a recognized risk factor for blood clots, so combined pills require particular consideration when someone has other factors that increase clot risk. They remain suitable for many people, but a healthcare professional should assess relevant medical history before prescribing them.
Progestin-only pills, or the mini-pill
Progestin-only pills contain no estrogen. They are often considered for people who should avoid estrogen-containing contraception. A 2026 systematic review available through the Centers for Disease Control and Prevention (CDC) found that the available evidence did not suggest an increased risk of venous blood clots with progestin-only pills. However, the certainty of the evidence was low or very low, so personal health factors still matter when choosing a contraceptive method.
Other contraceptive methods have different risk profiles. Do not assume that every hormonal method carries the same risk or that a progestin-only method is automatically suitable for everyone with a history of blood clots. A clinician can help compare options based on your circumstances.
Who has a higher risk of DVT while taking the pill?
Birth control is only one possible contributor to blood clot risk. The CDC explains that the chance of developing DVT or a pulmonary embolism increases when several risk factors occur together. Relevant factors include personal medical history, inherited conditions, smoking, and periods of reduced movement.
- Previous blood clots: A history of DVT or pulmonary embolism can increase the risk of another clot.
- Family history or inherited clotting conditions: Having a close relative with blood clots or a known inherited clotting disorder can affect contraceptive choices.
- Smoking: Smoking increases vascular risks, and age is also important when assessing the safety of combined hormonal contraception. People older than 35 who smoke should discuss the suitability of combined pills with their healthcare professional.
- Recent surgery or limited movement: Major surgery, prolonged bed rest, a leg cast, or long periods of sitting can increase the chance of a clot.
- Pregnancy and recent childbirth: Clot risk rises during pregnancy and remains elevated after delivery, particularly during the early postpartum period.
- Other medical conditions: Obesity, cancer, certain chronic illnesses, and some conditions that affect blood clotting may add to the overall risk.
Having one or more of these factors does not automatically mean that a person will develop DVT. It does mean that contraceptive suitability deserves careful review. Tell your prescriber about personal or family blood clot history, smoking, recent surgery, and any major changes in your health before starting or changing a hormonal contraceptive.
What symptoms of DVT should you look out for?
DVT can sometimes cause noticeable changes in one leg or arm. According to MedlinePlus, possible symptoms include swelling, pain or tenderness, warmth, and redness of the affected area. These symptoms can have other causes, too, so they cannot confirm a blood clot on their own.
- Swelling in one leg or arm, particularly when the other side is not similarly affected.
- Pain or tenderness in the affected limb.
- Skin that feels warmer than the surrounding area.
- Redness or another change in skin colour.
If you develop unexplained swelling or pain in one leg while taking a combined contraceptive pill, seek urgent medical assessment rather than waiting for a routine appointment. A healthcare professional can review your symptoms and medical history and decide whether tests, such as an ultrasound or a blood test, are needed.
When is a blood clot a medical emergency?
A clot that travels to the lungs can cause a pulmonary embolism. The MedlinePlus pulmonary embolism information page identifies symptoms such as sudden shortness of breath, chest pain, coughing up blood, a rapid heartbeat, lightheadedness, or fainting. These symptoms require emergency medical attention.
Call your local emergency number immediately if you develop unexplained difficulty breathing, chest pain, coughing up blood, or fainting, especially if you are also experiencing leg swelling or pain. Do not wait for symptoms to improve or rely on changing your contraceptive pill as a substitute for urgent medical care.
How can you reduce your risk when choosing birth control?
The most useful step is to review your medical history with a qualified healthcare professional before starting a combined pill. Your clinician can consider any previous blood clots, family history, smoking, age, other health conditions, recent childbirth, and planned surgery or prolonged immobility. These details help determine whether estrogen-containing contraception is appropriate or whether another method may be a better option.
If you already take a combined pill and have developed a new medical condition or expect to undergo major surgery, contact your healthcare professional to discuss whether your contraceptive plan needs to change. Do not alter your contraception without considering how you will continue to prevent pregnancy, unless you are receiving urgent medical instructions for a suspected or confirmed clot.
Options may include a progestin-only pill, an implant, an intrauterine contraceptive device, or a nonhormonal method. Each option has its own benefits, limitations, and safety considerations. The best choice depends on your medical history, contraceptive needs, and preferences.
Can you take birth control pills if you have had DVT before?
A previous DVT does not mean that every form of contraception is unsuitable, but it can substantially affect which methods are recommended. Combined pills containing estrogen may be inappropriate for people with a history of blood clots, particularly when additional risk factors are present. A healthcare professional should assess the circumstances of the previous clot, any treatment being taken, and the risk of another event before advising on contraception.
Do not restart a previously prescribed combined pill after a blood clot without medical guidance. If you take medication to prevent further clots, tell your clinician before starting, stopping, or changing any hormonal contraceptive, because your contraceptive and clot-prevention plans need to be considered together.
Does the benefit of birth control outweigh the risk?
For many people, combined birth control pills provide reliable pregnancy prevention and may also help with menstrual symptoms. Their small increased risk of blood clots does not mean they are unsuitable for everyone. The decision should balance their benefits against individual risk factors and available alternatives.
If you are considering the pill for the first time, ask your healthcare professional which formulation best fits your medical history. If you are already taking one and have concerns about DVT, arrange a review rather than making a change based only on general risk estimates. Any symptoms that could indicate a blood clot need prompt assessment, regardless of the contraceptive method used.