Hormones for menopause are safe, study finds. Here's what changed

The benefits of hormone therapy for the treatment of menopause symptoms outweigh the risks. That's the conclusion of a new study published in the medical journal JAMA.

"Among women below the age of 60, we found hormone therapy has low risk of adverse events and [is] safe for treating bothersome hot flashes, night sweats and other menopausal symptoms, " says study author Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women's Hospital. This is a departure from the advice many women have been given in the past.

The new analysis is based on two decades of follow-up data from the Women's Health Initiative study, which followed thousands of women taking hormone replacement therapy. The study was halted after it was found that women taking Prempro, which is a combination of estrogen and progestin, had higher risks of breast cancer and stroke.

"The findings were surprising," Manson says, pointing out that the reason the randomized trial was conducted was because scientists were trying to determine if hormone therapy decreased the risk of heart disease and other conditions.

After the initial findings came out, many women abruptly stopped the therapy. Prescriptions plummeted, and many healthcare providers still hesitate to recommend hormone therapy. But menopause experts say it's time to reconsider hormone therapy, because there's a lot known now that wasn't known two decades ago.

Most significantly, there are now different types of hormones — delivered at lower doses — that are shown to be safer.

"Women should know that hormone therapy is safe and beneficial," says Dr. Lauren Streicher, a clinical professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine.

Looking back, Dr. Streicher says, it's clear the Women's Health Initiative study was flawed and that some of the risks that were identified were linked to the type of hormones that women were given.

"We learned what not to do," Streicher says. The type of progestin used, medroxyprogesterone acetate, was "highly problematic," she says. This may have been linked to the increase in breast cancer seen among women in the earlier study. "So we don't prescribe that anymore," Streicher says.

Increasingly, other types of hormones are used, such as micronized progesterone which does not increase the risk of breast cancer, Streicher says. Micronized progesterone is a bioidentical hormone that has a molecular structure identical to the progesterone produced by women's ovaries, and tends to have fewer side effects.

Another problem with the study was the age of the women enrolled. Most of the women were over the age of 60, Streicher says. "And we know that there is a window of opportunity when it is the safest to start hormone therapy and that you get the most benefit." That window is typically between ages 50 and 60, she says.

Another risk identified in the Women's Health Initiative study, was an increased incidence of pulmonary embolism among women taking hormones. A pulmonary embolism is a blood clot that blocks blood flow to the lungs.

Since women in the study were taking estrogen orally, by pill, this may have increased their risk, Streicher says. A better option for people at risk of clots is to take estrogen through the skin, via a patch, a cream or gel.

"The advantage of a transdermal estrogen is that it is not metabolized by the liver," Streicher says. "And because it's not metabolized by the liver, we don't see that increase in blood clots."

With a range of hormone therapies available now, Streicher says there's not a one-size fits all approach. "Hormone therapy is beneficial way beyond the benefits to just helping with hot flashes," she says. Ongoing research points to protection against bone loss and heart disease, too.

Streicher says women should talk to their healthcare providers about what options may best suit their needs.

This story was edited by Jane Greenhalgh

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