Blood clots much more common among obese women taking combination birth control pills

Obese women who take certain oral contraceptives face a heightened risk of venous thromboembolism (VTE), according to new research out of Italy. The risk of developing a potentially fatal blood clot is especially high among women under the age of 40.  

The full study was published in ESC Heart Failure, a journal of the European Society of Cardiology.[1] The analysis focused on combined oral contraceptives (COCs), which contain both estrogen and progestin. COCs are a common form of birth control often referred to as “the pill.”

The study’s authors reviewed the latest research focused on “the cardiovascular impact of obesity and contraceptive use.” Why is this so important? Obesity is a known risk factor of both VTE and arterial thromboembolism, the group noted, and women younger than 40 years old face an even higher risk of these serious conditions. Also, they added, the worldwide prevalence of obesity nearly tripled from 1975 to 2016, making this a topic that is only growing in importance as time goes on.

Overall, the researchers found that a woman’s risk of VTE increases substantially when she takes combined oral contraceptives. This, combined with the built-in risk factors associated with obesity, mean that an obese patient taking a COC is up to 24 times more likely to develop VTE than a non-obese patient who is not taking a COC.

“It is well established that both obesity and estrogen-containing contraceptives are risk factors for VTE,” co-author Giuseppe Rosano, MD, PhD, president of the Heart Failure Association and a cardiologist with IRCCS San Raffaele in Rome, said in a prepared statement. “Despite this, obese women continue to receive these drugs. The scientific evidence indicates that obesity and combined oral contraceptives have a synergistic effect on VTE risk and this should be considered in prescribing decisions. Progestin-only products, including pills, intrauterine devices, or implants are a safer alternative to the combined pill in women carrying excess weight.”

Rosano also said at-risk women should consider making key lifestyle changes such as  “quitting smoking and increasing their physical activity levels” to help reduce their long-term risk of VTE.

Michael Walter
Michael Walter, Managing Editor

Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.

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