TRAINING and EDUCATION
Patient Education
WOMEN and the
RISK of BLOOD CLOTS
Nearly 900,000 people are affected by blood clots each year, leading to approximately
100,000 blood clot-related deaths annually. Dangerous blood clots such as deep-vein
thrombosis (DVT) often form in the veins of a person’s arm or leg. If a DVT is left untreated,
the clot can break loose and travel to the lungs (pulmonary embolism [PE]), which can be
life-threatening.
Men have a higher overall risk of thrombosis than women, but women have risks due to
pregnancy, birth control, and postmenopausal hormone therapy that men do not. These
risks are generally attributed to estrogen, a key ingredient in birth control pills, patches,
and rings, and in postmenopausal hormone therapy.
Choices related to family planning, pregnancy, and the treatment of menopausal
symptoms can affect a woman’s risk for developing a blood clot. This is further increased
if a woman has previously experienced a blood clot, has a family history of blood clots, or
has been diagnosed with a genetic or acquired clotting disorder. Nearly half of people who
experience a DVT do not experience symptoms, so it is important for women to learn the
risks associated with blood clots.
Read below for more information about the risk factors for developing a blood clot that
are specific to women.
This “Patient Education” tear sheet was produced in collaboration with the National
Blood Clot Alliance (stoptheclot.org).
In both men and women, certain factors increase a
person’s risk of experiencing a blood clot, including:
• hospitalization
• surgery
• traumatic physical injury
• immobility
• smoking
• obesity
• older age
• family history of clotting disorders
Symptoms of blood clots in the legs or arms include
pain and swelling, and skin may be discolored and/
or warm to the touch. Symptoms of blood clots in the
lungs include chest pain (particularly when taking a
deep breath), coughing up blood, shortness of breath,
and an accelerated heart rate.
Birth Control and Family Planning
Birth control methods that contain estrogen (i.e.,
birth control pills, patches, and rings) and synthetic
progesterone (progestin) can increase a woman’s risk
for blood clots because they cause an increase in
the level of clotting factors or clotting proteins in a
woman’s body.
The most common method of birth control in the
United States is the birth control pill, and the vast
majority of women taking estrogen-containing birth
control pills will not experience a blood clot. The
absolute risk of developing a blood clot is about 1 in
300 women. Some newer birth control methods, such
as patches and rings, pose an even greater risk because
the amount of estrogen absorbed from the patches is
reported to be 60 percent higher than the amount of
estrogen delivered by pills.
Safe birth control methods that do not include
estrogen include:
• barrier methods
• spermicides
Cut out and give to a patient
• progestin implant
• copper intrauterine device (IUD)
• progestin IUD
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