This could be a tough pill to swallow. An estimated 250 million women worldwide are believed to use some form of hormonal contraception. Past research has suggested a link between the use of synthetic hormones to prevent pregnancy and an increased risk of stroke and heart attack.

The most common formulation of birth control pills has been linked to a doubling of relative risk of heart attack and stroke, a new study finds.

A recent study found that vaginal rings and even skin patches had used the same combination of hormones that pose similar health risks.