Oral contraceptives used for birth control are the most popular form of birth control in the U.S. When the birth control pills contain estrogen, or women use estrogen cocktails in hormone replacement therapies, the risk for developing a blood clot is increased when compared to a women not taking supplemental estrogen. The estrogen-containing medications alone increase the risk of developing a blood clot, but when combined with the genetic predisposition to develop a blood clot known as thrombophilia, the risk is unmanageable and dangerously reckless.
What is Thrombophilia?
"Thrombophilia" is the term given to a collection of genetic blood clotting disorders that cause an increased tendency to develop blood clots. Thrombophilia includes disorders such as Factor V Leiden, increased API-1, and antiphospholipid syndrome. Thrombophilia is the opposite of the more well-known and less common disorder hemophilia. A person with thrombophilia has small blood clots flowing throughout their blood due to an increased production of clots and an underproduction of the enzymes necessary to dissolve blood clots. These small blood clots often cause no problems or outward symptoms, so the blood clotting disorder goes undiagnosed. The diagnosis is made when the small clots join together and become large enough to cause a stoke, heart attack, pulmonary embolism, deep vein thrombosis (DVT), or recurrent miscarriages.
A diagnosis of a thrombophilia blood clotting disorder does not ensure that a patient will experience a life-threatening blood clot associated emergency, and dangerous blood clots can be experienced by individuals with no genetic clotting disorder. However, thrombophilia greatly increases the risk that an individual will experience a large blood clot, and steps should be taken to reduce the risk. Long periods of immobility, obesity, smoking, and some medications, including estrogen-containing medications, should be avoided when possible.
How Does Estrogen Affect Thrombophilia?
Stop the Clot Org from the National Blood Clot Alliance states that estrogen increases the amount of clotting factor in the blood, and because of this, is suspected to be the reason for the increased risk of blood clots during pregnancy. Andra James, MD of Duke University writes, "the absolute risk of a blood clot is small... but for women with thrombophilia or a history of thrombosis, the risk becomes substantial." The increase in clotting factor caused by estrogen is one of the reasons women are urged not to smoke while taking oral contraceptives containing estrogen. The combination of these two risk factors for blood clots – estrogen and smoking – increase the overall risk for a potentially life-threatening clot too greatly to be ignored. The same is true of a genetic predisposition to blood clots found in patients with thrombophilia. Unfortunately, because of the lack of symptoms, thrombophilia goes largely undiagnosed, so this particular combination of risk factors that increase the risk of blood clots remains unnoticed.
The Dangers of Estrogen Replacement Therapy and Birth Control Pills
According to Net Wellness from the University of Cincinnati, Ohio State University, and Case Western Reserve University, "Use of estrogen-containing birth control pills increases the chance that any woman will develop a blood clot by about five-fold. For women with a thrombophilia, like factor V Leiden, the risk to develop a blood clot is about 32 times higher if they are taking estrogen-containing birth control pills." Medications containing estrogen increases a woman's risk for conditions associated with blood clots, but in combination with a genetic predisposition to develop clots, the risk is unacceptable.
NCBI, developed at the University of Washington, published a study called Factor V Leiden Thrombophilia stating that "Women with inherited thrombophilic disorders, such as factor V Leiden thrombophilia, tend to develop thrombotic complications sooner, with a much higher risk for thrombosis during the first year of oral contraceptive use." The findings were the same for estrogen-containing hormone replacement therapies.
Women with blood clotting disorders should avoid any estrogen-containing medications including oral contraceptives and post-menopausal hormone replacement therapies because the risk of developing a large blood clot is too great. Another option for these women are progestin-only contraceptives, and hormone-free birth control methods. One risk factor for thrombosis (or the development of a blood clot) alone is not enough to be of great concern, but steps should be taken to reduce controllable risk factors such as smoking, obesity, immobility, and estrogen-containing medications, especially in the presence of a genetic blood clotting disorder.
Sources:
American Society of Hematology: Blood Clots. (accessed October 6, 2010).
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Chasity Goddard - Chasity Goddard holds a BA degree from the University of TN. Her wide-ranging interests and research skills pull her in various ...
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