Low-Dose Birth Control Pill May Up Heart Risk
But Researchers Say Risk of Heart Attack and Stroke Still Very Low for Most Women
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
"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