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Women's Health

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Joan Bengtson, M.D., is assistant professor of obstetrics, gynecology and reproductive biology at Harvard Medical School and a member of the Department of Obstetrics, Gynecology & Reproduction at Brigham and Women's Hospital.


My doctor recently switched my birth control pills from Yasmin to Seasonale (only have a period every three months). Is there a greater risk of blood clots and strokes when you use a birth control such as Seasonale verses Yasmin?


There is no specific evidence that using Seasonale increases the risk of blood clots and strokes compared with Yasmin. Seasonale is a low-dose oral contraceptive pill taken continuously for 11 weeks and then stopped for one week to allow for a menstrual flow. Other pills are used on a one-month cycle so a period occurs every four weeks.

Modern oral contraceptive pills have a very low dose of estrogen and progesterone compared to the original birth control pills. Low-dose pills are much safer with regard to the risk of blood vessel and heart diseases. Healthy, nonsmoking women have a very minimal risk of stroke. Women who smoke should not use the pill after age 35.

Blood clots are associated with birth control pills, though the absolute risk is quite low (approximately two to four episodes per 10,000 users). There is some concern that pills containing the newer progesterone types (called desogestrel and gestogene) have a higher risk of blood clots than those containing other forms of progesterone. Anyone considering birth control pills should review the risks with her doctor to choose the safest one for her situation.

Author: Joan Bengtson, M.D.
Date Last Reviewed: 11/26/2007
Date Last Modified: 7/20/2009
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