Combined birth control pill linked to increased risk of blood clots in obese women
According to a review article published today in ESC heart failure, a journal of the European Society of Cardiology (ESC).
Study author Professor Giuseppe Rosano of IRCCS San Raffaele Pisana, Rome, Italy, said: “It is well established that obesity and estrogen-containing contraceptives are risk factors for VTE. Despite this, obese women continue to receive these drugs. Scientific evidence indicates that obesity and combined oral contraceptives have a synergistic effect on VTE risk and this should be considered in prescribing decisions. “
This review article highlights the latest evidence on the independent effects of obesity and contraceptives, and their synergistic effects, on VTE risk and provides clinical recommendations. VTE refers to a blood clot in a vein and includes two life-threatening conditions: deep vein thrombosis and pulmonary embolism.
The World Health Organization estimates that the global prevalence of obesity almost tripled between 1975 and 2016, with 15% of adult women being obese. The risk of VTE increases progressively with body mass index (BMI) and in obese women it is more than double that of non-obese women. Obesity has the greatest impact on VTE women under 40, who have a five times higher risk than non-obese women. Professor Rosano noted: “The particularly high risk in obese women under 40 is significant, as it is at this age that many seek contraception.”
Combination oral contraceptives are associated with a high likelihood of VTE, with users having a three to seven times higher likelihood of VTE compared to non-users. In contrast, progestins are not associated with an increased risk of VTE.
The combination of overweight/obesity and the use of combined oral contraceptives potentiates the likelihood of blood clots in women of childbearing age. For example, a large population-based study found that being overweight and obese were associated with 1.7-fold and 2.4-fold increased risks of VTE, respectively. However, among users of the combination pills, the risk of VTE was 12 times higher in overweight women and 24 times higher in obese women – compared to non-users of normal weight.
Professor Rosano said: “Obese women taking contraceptives are vulnerable to VTE and should take steps to limit their other predisposing factors for cardiovascular disease, such as stopping smoking and increasing their level of physical activity.”
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Material provided by European Society of Cardiology. Note: Content may be edited for style and length.