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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 Hormonal Contraception and using other medications at the same time.

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.

Overview

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). But the risk for DVT or PE is overall very low with hormonal contraceptives.

Birth control pills

In the past, combination birth control pills contained a higher dose of estrogen. The higher dose increased the risk of DVT and PE. Now the combination pill contains a lower dose of estrogen. 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.

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.

The birth control patch

The patch delivers more estrogen than the low-dose birth control pills do. Women who use the patch are slightly more likely to get dangerous blood clots in the legs and lungs than women who use birth control pills. So talk to your doctor about your risks before you use the patch.

Things that can increase your risk for a blood clot

Some of the things that can increase your risk for a blood clot include:

Slowed blood flow

When blood doesn't flow normally, clots are more likely to develop. Reduced blood flow may result from long-term bedrest, such as after a surgery, injury, or serious illness. Or it may result from sitting for a long time, especially when travelling long distances.

Abnormal clotting

Some people have blood that clots too easily or too quickly. Things that may cause increased clotting include:

  • Having certain blood problems that make blood clot too easily. This is a problem that may run in families.
  • Having certain health problems, such as cancer, heart failure, stroke, or severe infection.
  • Being pregnant. The risk of getting blood clots increases both during pregnancy and shortly after delivery or after a caesarean section.
  • Using hormonal forms of birth control, gender-affirming hormone therapy, or hormone therapy for menopause.
  • Smoking.

Injury to the blood vessel wall

Blood is more likely to clot in veins and arteries shortly after they are injured. Injury can be caused by a recent medical procedure or surgery that involved your legs, hips, belly, or brain. Or it can be caused by an injury, such as a broken hip.

References

Citations

  1. Abramowicz M (2010). Choice of contraceptives. Treatment Guidelines From The Medical Letter, 8(100): 89–96.
  2. 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.

Credits

Current as of: August 2, 2022

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine