Contraceptive pill and venous thromboembolism

A study published this week in the BMJ adds to the body of research supporting the theory that the

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newer contraceptive pills pose an increased risk of serious blood clots.  The authors of  the study, Use of combined oral contraceptives and risk of venous thromboembolism, looked at a series of population based, case-control studies of over 10,000 women aged 15-49 years with a first diagnosis of venous thromboembolism in 2001-13.  Their conclusion was that "risks of venous thromboembolism associated with combined oral contraceptives were, with the exception of norgestimate, higher for newer drug preparations than for second generation drugs."

Putting that study into perspective is a useful article in The Conversation today by Terri Foran from the University of New South Wales. In Don't panic about the pill – it's safer than driving to work, Foran points out that the risk of blood clots has been know for many years, even with older contraceptive preparations, and while the figures in the BMJ study are true, the risk is still very small.  "Although a doubling of clotting risk sounds alarming, it actually translates to an additional four to six cases per 10,000 users of the newer pills a year." and that "the risk of a woman dying from a road accident is approximately 25 times that of death from a pill-related clot."

Find the fulltext of the BMJ article on CIAP if you are a NSW Health employee.  Otherwise, contact your librarian.

Vinogradova, Y., Coupland, C. & Hippsley-Cox, J. Use of combined oral contraceptives and risk of venous thromboembolism: nested case-control studies using the QResearch and CPRD databases  BMJ 2015;350:h2135.