Low-Dose Birth Control Pill May Up Heart Risk

But Researchers Say Risk of Heart Attack and Stroke Still Very Low for Most Women

By Salynn Boyles
WebMD Medical News

Reviewed By Brunilda  Nazario, MD
on Thursday, July 07, 2005

July 7, 2005 -- Low-dose birth control  pills are widely considered to be safer than the pill of the past, but a new review suggests that they still carry an increased risk for heart attack and stroke.

The risk appears to be quite small for most women, but it could be much higher for those already at risk for heart disease, researchers report. That includes overweight women at high risk for diabetes and women with a condition known as polycystic ovary syndrome.

Researcher John E. Nestler, MD, tells WebMD that studies are needed to better understand the risks associated with oral contraceptive use in these women.

"I think it is quite reasonable to assume that women who already have an increased risk for cardiac disease may be particularly vulnerable," he tells WebMD. "But there is not a single study out there looking specifically at oral contraceptive use in this group."

Doubling of Risk

Heart attack and stroke are rare in women of childbearing age, but they do occur. Studies clearly link earlier generations of the pill to an increased risk for these events. Less is known, however, about the risks associated with today's oral contraceptives, which contain much lower doses of estrogen than the earlier versions of the pill.

In an effort to clarify this risk, Nestler and colleagues from Virginia Commonwealth University and the University of Sherbrooke in Sherbrooke, Quebec, reviewed relevant studies that included women taking low-dose oral contraceptives conducted between 1980 and 2002.

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 nonusers. The risk returned to normal, however, when the women stopped taking the pill.

To put the findings in perspective, if a 40-year-old woman's risk of dying from heart disease in 10 years is five in 1,000, it increases to 10 in 1,000 if she takes low-dose oral contraception.

"Obviously, this risk is extremely small, so I don't think this finding will have an impact on the use of birth control pills for contraception [among women of normal risk]," Nestler says.

Rethinking PCOS Treatment

He points out, however, that oral contraceptives are the preferred treatment for polycystic ovary syndrome (PCOS), a hormonal imbalance that is one of the most common causes of infertility. The syndrome is also associated with a high risk of type 2 diabetes, related to insulin resistance, abnormal periods, and excess male hormones.

It is estimated that as many as 2 million women in the U.S. have both PCOS and metabolic syndrome, a cluster 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.

Nestler points out that a woman with PCOS may end up taking oral contraceptives for several decades to treat many of the symptoms of the condition. They are also used to make menstrual cycles regular -- thought to be key in treating the condition.

Nestler says insulin-sensitizing drugs like Glucophage may be a safer alternative to contraceptives in women who may already have a higher-than-normal risk for heart disease.

"There is at least the possibility that oral contraceptives may not represent optimal therapy for PCOS and perhaps metabolic syndrome, and I think this deserves study," he says.

New York cardiologist Nieca Goldberg, MD, tells WebMD that even young women who begin using oral contraceptives should be screened for heart disease risk. Goldberg is chief of the Women's Heart Program at Lenox Hill Hospital in New York and is the author of the book Women are Not Small Men: Life-Saving Strategies for Preventing and Healing Heart Disease in Women.

"When a woman is considering her birth control options, that is an ideal time to be screened for heart disease risk," she says. "If we did that on a routine basis we could identify high-risk women early and reduce heart disease later in life."

SOURCES: Baillargeon, J., The Journal of Clinical Endocrinology and Metabolism, July 2005; vol 90: pp 3863-3870. John E. Nestler, MD, professor and chairman, division of endocrinology and metabolism, Virginia Commonwealth University School of Medicine, Richmond, Va. Nieca Goldberg, MD, chief of Cardiac Rehabilitation and Prevention Center, Lenox Hill Hospital, New York; spokeswoman, American Heart Association. Framingham data on cardiac risk.

© 2005 WebMD Inc. All rights reserved.


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