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Birth control pills
Risk of Blood Clots with the Pill?
Originally Published: September 08, 1995 ~ Last Updated / Reviewed on: November 09, 2007
 
Dear Alice,

I'm concerned about the chance of blood clots when using The Pill as a contraceptive method. The pamphlets say that the possibility of blood clots is a major risk but do not go into any detail as to the frequency that this happens, statistics on such occurrences, or whether or not symptoms occur before a blood clot, etc. I need more information!

Thanks,
Nervous

 

Dear Nervous,

The most serious complications attributable to birth control pills have been cardiovascular and circulatory system diseases, including blood clots. Clots are particularly dangerous because they can travel to distant parts of the body and relocate in places such as the lungs. However, as the Center for Disease Control and Prevention states, in most healthy women, estrogen and progestin together have no clinically significant impact on clotting.

Cardiovascular diseases, including blood clots, are more likely to occur in women who:

  • smoke
  • are sedentary
  • are overweight
  • are more than 50 years old
  • have high blood pressure
  • are diabetic
  • have a history of heart or vascular disease
  • and/or have an elevated cholesterol level

For most women, these factors are much more important in determining a risk for cardiovascular disease than taking low-dose combined oral contraceptives (the most commonly prescribed birth control pills). These newer low dose pills have less effect on blood clotting than earlier pills, and there is less risk for women who don't have any of the other risk factors listed above for cardiovascular disease. If you have any of the predisposing factors to cardiovascular disease, the combined pill may not be for you. If you don't, the risk from these pills alone is relatively small.

When blood clots do appear, it seems to be the estrogen in the combined pills that activates the response. Although there are tests that can help a clinician to predict who will not clot when on hormonal contraception, no tests exist that can predict who will clot abnormally while taking pills. As with many decisions about your health, having an honest chat about your medical history and concerns with your provider is the best way to make an informed and safe decision about using birth control. You may decide that your next annual exam is a great opportunity to talk about contraceptive options, or you may decide to make an appointment specifically to discuss birth control, clots and your personal risk. Students at Columbia may call x4-2284 or schedule an appointment online through Open Communicator.

In the mean time, if you are concerned that you may develop a clot, there are several warning signs that can possibly reveal one. A good way to remember them is to think of the word ACHES, short for

  • Abdominal pain,
  • Chest pain (and shortness of breath),
  • Headaches (especially those that are new, severe, or associated with persistent dizziness, difficulty speaking, fainting, numbness or weakness in extremities),
  • Eye problems (blurred vision or loss of vision), and
  • Severe leg pain (and/or redness and swelling in the calves or thighs).
If you are having a set some or all of the ACHES symptoms, it is important to seek medical advice immediately. Call your regular health care provider, or visit an urgent or emergency care department. Hope this information was helpful!
Alice

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