Hormonal Birth Control: Risk of Blood Clots
British Columbia Specific Information
Birth control can help prevent pregnancy. There are many types of birth control available. Speak with your health care provider to help decide which type is right for you and your partner.
Hormone-based birth control contains hormones such as estrogen and progestin. Certain medications may make your hormone-based birth control not work properly or not at all. For more information, see HealthLinkBC File #91a Using Hormone-based Birth Control with Other Medications.
Emergency contraception helps to prevent pregnancy after unprotected sex, or failed birth control. For more information about emergency contraception, see HealthLinkBC File #91b Emergency Contraception (EC).
Birth control cannot prevent sexually transmitted infections (STIs), but using a condom will reduce your risk. For more information about birth control and sexual health, visit Options for Sexual Health and Smart Sex Resource. To learn more about STIs, see our HealthLinkBC Files - Sexually Transmitted Infections Series.
You may also call 8-1-1 to speak with a registered nurse or pharmacist. Our nurses are available anytime of the day, every day of the year. Our pharmacists are available every night from 5:00 p.m. to 9:00 a.m.
In some women, the estrogen in combination hormonal birth control methods increases the risk of a blood clot in a leg (deep vein thrombosis, or DVT) or a blood clot in a lung (pulmonary embolism, or PE). A blood clot in a leg vein can travel through the circulation system and cause pulmonary embolism.
The risk for DVT or PE is overall very low with hormonal contraceptives. In the past, combination birth control pills contained a higher dose of estrogen, which increased the risk of DVT and PE. Now the combination pill contains a lower dose of estrogen, and the risk is reduced. The risk for DVT or PE is actually higher for a pregnant women than for non-pregnant women taking hormonal contraceptives.
Combination hormonal birth control pills that contain the progestin called desogestrel increase the risk of blood clots more than birth control pills that contain other types of progestin.footnote 1 The progestin called drospirenone (found in pills such as YAZ or Yasmin) also might have a greater risk of blood clots than other types of progestin.footnote 2 Talk to your doctor about the risk of blood clots when deciding which pill is right for you.
The birth control patch delivers more estrogen than the low-dose birth control pills do. Health Canada warns that women using the patch are slightly more likely to get dangerous blood clots in the legs and lungs than women using birth control pills. So talk to your doctor about your risks before using the patch.
The known risk factors for blood clots (DVT or PE) include:footnote 3
- Pregnancy and the first 6 weeks after delivery.
- Personal or family history of blood clots.
- Surgery. Birth control pills are usually stopped within 1 month of major surgery to decrease the risk of a blood clot. The risk needs to be balanced against the risk of an unintended pregnancy by stopping the pills.
- Coagulation disorders, such as factor V Leiden mutation. This is a genetic blood clotting problem.
- Inactivity, such as during long distance travel in cars or airplanes.
- Abramowicz M (2010). Choice of contraceptives. Treatment Guidelines From The Medical Letter, 8(100): 89–96.
- U.S. Food and Drug Administration (2011). FDA Drug Safety Communication: Updated information about the risk of blood clots in women taking birth control pills containing drospirenone. Available online: http://www.fda.gov/Drugs/DrugSafety/ucm299305.htm.
- American College of Obstetricians and Gynecologists (2006, reaffirmed 2008). Use of hormonal contraception in women with coexisting medical conditions. ACOG Practice Bulletin No. 73. Obstetrics and Gynecology, 107(6): 1453–1472.
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Femi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology
Current as ofMay 22, 2015
Current as of: May 22, 2015
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