Women who enter menopause at a normal age won’t get much of a heart benefit from taking hormones, according to a fresh look at some past research.
There were some modest benefits among women who took hormones within the first 10 years of menopause, but they also had an increased risk of blood clots, which can cause strokes or travel to the lungs.
The results don’t mean there is no place for hormones after menopause, said Dr. Adrienne Bonham, who was not involved with the analysis. “It’s just that if you’re doing it to prevent cardiovascular disease, you shouldn’t be doing that.”
It’s also important to note that the results do not apply to women who enter menopause prematurely, for example in their 30s, said Bonham, the head of obstetrics and gynecology at the University of Rochester Medical Center in New York.
The fact that a woman's estrogen and progesterone levels fall after menopause, while her heart disease risk rises, originally led to the idea that hormone replacement therapy might protect against heart risks.
In the late 1990s and early 2000s, large, rigorous studies found that hormone replacement did not protect against heart disease after menopause. In fact, one study ended early when researchers saw that estrogen plus progestin appeared to increase the risks of stroke, heart disease and breast cancer.
The American College of Obstetrics and Gynecology does not recommend the use of hormones after menopause to prevent heart disease. However, women in early menopause without heart disease may consider hormones to help with menopause symptoms.
In recent years, additional evidence has suggested there may be some benefit from hormones for the heart health of women when they first enter menopause, said Dr. Henry Boardman from the University of Oxford, who led the new analysis.
To assess the question, the researchers combined results from 19 randomized trials that included 40,410 women from several countries. About half took some sort of hormone therapy and the other half took a placebo for comparison.
The women had all gone through menopause and were followed for anywhere from seven months to a little over 10 years.
Overall, there was no evidence that taking hormones prevented heart disease or its complications in women with or without existing heart disease. If anything, it appeared to increase the risk of stroke, according to findings published by The Cochrane Collaboration, an international organization that evaluates medical research.
“These confirm existing national and international guidelines that hormone therapy should not be taken to prevent cardiovascular disease,” Boardman said.
To evaluate the question known as the “timing hypothesis” about a possible benefit from hormones for heart health among women when they first enter menopause, the researchers looked at data on those who took hormones in the first 10 years after menopause.
According to Boardman, the results suggested that if 1,000 women under age 60 were taking hormones over seven years, there would be six fewer deaths and eight fewer cases of heart disease, but also five more cases of blood clots, compared to similar women not taking hormones.
He said the results among these younger women should also be interpreted with caution, because the data weren’t originally intended to evaluate the “timing hypothesis.”
“I think the results raise interesting questions,” he said. “There is valid scientific hypothesis underpinning this. I hope this review leads to further research.”
Boardman said it’s important that women and their healthcare providers have the best information to determine whether hormone therapy is the right treatment.
Different groups of women have different risk factors, said Bonham, who added that most doctors – especially specialists – are knowledgeable about the risk and benefits.