Overweight and obese women are in danger of developing life-threatening blood clots from birth control pills, new research reports.
Commonly known as "the pill", combined birth control pills are a widespread form of contraception that come with a risk of blood clots. A new study has spelled out the staggering risks of developing serious blood clots for some women on the pill.
Obese women taking the pill are 24 times as likely to develop clots, and for overweight women, the risks were twelve-fold. Researchers recommended alternative forms of birth control as a safer alternative for women in both groups.
Blood clots, also known as venous thromboembolism (VTE), are a disorder that includes two life-threatening conditions - deep venous thrombosis and pulmonary embolism.
Deep vein thrombosis (DVT) happens when a blood clot forms in a deep vein, which is usually in the lower leg, thigh, or pelvis. A pulmonary embolism (PE) refers to when a clot breaks loose and travels through the bloodstream to the lungs.
It is "well established" that obesity and contraceptives with oestrogen - like the pill - are risk factors for blood clots, said study author Professor Giuseepe Rosano.
"Despite this, obese women continue to receive these drugs," noted Prof Rosano. "The particularly high risk in obese women under 40 is important, since it is at this age that many seek contraception.
"Obese women taking contraceptives are vulnerable to VTE and should take steps to limit their other predisposing factors for cardiovascular disease, for example by quitting smoking and increasing their physical activity levels."
The scientist recommended other birth control options, adding: "Progestin-only products, including pills, intrauterine devices, or implants are a safer alternative to the combined pill in women carrying excess weight."
Published in the journal ESC (European Society of Cardiology) Heart Failure, the review article highlights the latest evidence on the independent effects of obesity and contraceptives.
The article cited a large population-based study that found the risks of developing blood clots was double in overweight women, with a two-and-a-half-fold risk for obese women.
For users of the combined pill, the risk of VTE was 12-fold higher in overweight women and 24-fold higher in obese women – when compared with normal weight non-users.
The Italian research team said: "Combined oral contraceptives are associated with an elevated likelihood of VTE, with users having a three- to seven-fold elevated likelihood of VTE compared with non-users."
They pointed out that the mini pill, which only contains the hormone progestin, is "not associated with an increased risk of VTE".
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