A new review suggests that low-dose birth control pills, which are generally considered to be safer than the pill of the past, still carries an increased risk for heart attack and stroke.
Although that risk appears to be quite small for the majority of women, it could apparently be much higher for those already at risk for heart disease.
The researchers say that includes overweight women at high risk for diabetes and women with a condition known as polycystic ovary syndrome.
According to researcher Dr John E. Nestler, further studies are needed in order gain a better understanding of the risks associated with oral contraceptive use in these women.
He says it is quite reasonable to assume that women who already have an increased risk for cardiac disease may be particularly vulnerable, but until now no studies have specifically looked at oral contraception use in this group.
Although heart attack and stroke are rare in women of childbearing age, they do occur, and other studies have clearly linked earlier generations of the pill to an increased risk in this respect.
The risks associated with today's oral contraceptives, which contain much lower doses of estrogen than the earlier versions of the pill, are less well researched.
Nestler and his colleagues from Virginia Commonwealth University and the Université de Sherbrooke (Québec, Canada) were eager to clarify this risk, so they reviewed relevant studies that included women taking low-dose oral contraceptives conducted between 1980 and 2002.
They found that overall, the risk of having a heart attack or stroke was found to be twice as high for low-dose oral contraceptive users as for non-users.
The risk returned to normal, however, when the women stopped taking the pill.
Nestler says that among among women of normal risk, this is extremely small, and the findings are not expected to impact on the use of birth control pills in this group.
However,as oral contraceptives are the preferred treatment for polycystic ovary syndrome (PCOS), a hormonal imbalance that is one of the most common causes of infertility, and the syndrome is also associated with a high risk of type 2 diabetes, related to insulin resistance, abnormal periods, and excess male hormones, the findings may be more relevant.
As many as 2 million women in the U.S. have both PCOS and metabolic syndrome, a combination of risk factors that increases heart disease and type 2 diabetes risk.
These women are typically overweight or obese and have insulin resistance. They may also have high blood pressure, low HDL "good" cholesterol, and high triglycerides, a blood fat also linked to diabetes risk.
Women with PCOS often take oral contraceptives for several decades to treat many of the symptoms associated with the condition.
Oral contraceptives are also used to regulate menstrual cycles, often thought to be a key in treating the condition, says Nestler.
He suggests that insulin-sensitizing drugs such as Glucophage may be a safer alternative to contraceptives, in women who may already have a higher-than-normal risk for heart disease.
New York cardiologist Nieca Goldberg, says that even young women who begin using oral contraceptives should be screened for heart disease risk.
Goldberg is head of the Women's Heart Program at Lenox Hill Hospital in New York, she is also the author of the book Women are Not Small Men: Life-Saving Strategies for Preventing and Healing Heart Disease in Women.
She says that when a woman is considering her birth control options, that is an ideal time to be screened for heart disease risk, and if that was done on a routine basis it would identify high-risk women early and reduce heart disease later in life.