There has been much concern about the risks of blood clots developing in either arteries or veins and the use of hormonal contraceptive pills. These risks are frequently a topic of conversation that patients bring up. I thought a quick review would be helpful.
The first oral contraceptives were introduced in the early 1960s and contained high doses of a combination of the hormones estrogen and progesterone. The dose of estrogen in the pill was found to be associated with an increased risk of blood clots forming in the veins of women…usually a major leg vein. Over the subsequent years, oral contraceptives containing smaller doses of both estrogen and progesterone were successfully developed to reduce these risks. The type of progesterone in these pills became a focus of discussion in the mid 1990s, when concern was raised that women taking oral contraceptives containing a newer form of progesterone such as desogestrel or drospirenone (eg,Yasmin) were at even more risk for developing blood clots than when taking drugs containing the original type of progesterone called, levonorgestrel . These newer progesterone drugs were formulated in an attempt to reduce the weight gain associated with oral contraceptive drug use.
Several large studies in Europe and recently our own FDA have confirmed that the older oral contraceptive pills doubled the risk of women forming blood clots in their veins compared to women who did not take these medications. The newer drugs alluded to above, further increase that risk. This clot risk is about 1/1000 per year in women taking the newer medications. In addition, women with the following medical conditions are recommended to avoid combination hormonal contraceptive drugs since their risk of developing blood clots in a vein or artery while on these drugs may be even higher:
- Pervious blood clot in an artery or vein
- Type I Diabetes Mellitus
- Inflammatory bowel Disease (Crohn’s or Ulcerative Colitis)
- Rheumatoid Diseases
- Predisposition to forming blood clots (“Hypercoagulable” disease either inherited or acquired, eg. Factor V Leiden Mutation).
In conclusion, oral combined hormonal contraceptive medications double the risk of blood clots in women’s veins. The newer drugs containing updated types of progesterone along with estrogen further increase this risk of forming spontaneous blood clots in veins. The risk of forming blood clots in an artery causing a stroke or a heart attack is slightly increased but only in women over age 35 who take drugs with the newer progesterone substitutes. Finally, there are a number of medical conditions in which use of combined hormonal drug therapy should be avoided.
Vein Specialists of Tampa is a medical practice exclusively dedicated to helping patients with a variety of vein conditions.