Blood's Gone Hormonal

Abnormal hormone syndrome with birth control can increase risk of blood clots in women

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) For most women, taking birth control pills is generally safe, and may even provide some protective benefits. However, there is a known risk that "the pill" can cause blood clots, especially in smokers. Is there an impact on women with an ovarian condition?

Women who have polycystic ovary syndrome (PCOS), combined with taking birth control pills, are twice as likely to have blood clots compared to women without the hormone imbalance, a new study has found.

The findings emphasize the importance of doctors to carefully choose the right birth control for each woman.

"Not all oral contraceptives are the same - consult your OB/GYN."

In polycystic ovary syndrome, there is an imbalance between the sex hormones estrogen, progesterone, and testosterone. Women with PCOS have difficulty releasing eggs from their ovaries, making it difficult to get pregnant. This causes cysts to grow in the ovaries. 

The study, led by Steven Bird, PharmD, with the Food and Drug Administration, looked at almost 90,000 women from the IMS LifeLink Health Plan Claims Database between May 2001 and December 2009. The database covers managed care organizations across the US.

All the women were on birth control pills, and a little more than half were diagnosed with the syndrome. The women ranged from 18 to 46 years of age.

Researchers tracked the number of women who reported having blood clots and the number who were on blood thinners. They excluded those who had a history of cardiovascular disease, cancer, blood clots or blood that couldn't easily clot.

Women with the hormone imbalance and who were on the pill together were more than twice as likely to get blood clots compared those who were on birth control pills without PCOS

"We found a two-fold increased risk of venous thromboembolism among women with PCOS taking combined oral contraceptives compared with matched controls," Dr. Bird said.

"We found a similar increased risk when we expanded the definition of PCOS by including its symptoms and treatment. We also found a 1.5-fold increased relative risk of venous thromboembolism among women with PCOS who were not taking contraceptives compared with matched controls."

The authors said that doctors should keep blood clot risk in mind when prescribing birth control to women with the syndrome.

The study, which was published online December 3 in the Canadian Medical Association Journal, was funded by a number of institutions, agencies and universities in Canada.

One of the authors was a consultant for Pfizer and the Observational Medical Outcomes Partnership. The other authors did not declare any conflicts of interest. 

Reviewed by: 
Review Date: 
December 12, 2012
Last Updated:
December 14, 2012