Use of estrogen tablets could increase risk of blood clots, study finds

Use of oral estrogen as part of menopausal hormone therapy could lead to a greater risk of blood clots, stroke and heart attack in women, according to a new study in the British Medical Journal.

The risk, however, was not observed in women who used transdermal hormone patches that are worn directly on the skin. And menopause experts on Long Island said the potential risks with oral estrogen are widely known and can vary by age and health.

"This is an observational study, not a randomized, double-blinded control study," said Dr. Stephanie Trentacoste McNally, director of OB-GYN services at Northwell Health’s Katz Institute for Women’s Health and clinical lead for its menopause and midlife medicine program. "It’s not something that can be easily translated into every population."

Menopausal hormone therapy can help women suffering from hot flashes, brain fog, sleep problems and other symptoms of perimenopause and menopause.

The study involved almost 100,000 women in Denmark between the ages of 50 and 69. Researchers looked at the medical records of women who had a first-time blood clot, stroke or heart attack and compared them with those who had not had any of those ailments.

Researchers found that women who took their hormone medicine orally had an increased risk of blood clots in their legs and lungs.

They found the risk of stroke and heart attack only in women who had taken a high dose of the oral hormone over one year.

Hormone therapy can also be taken via a patch or gel applied to the patient’s skin.

The authors of the study admitted the results may "not apply to other more ethnically diverse populations" and there was a lack of data on age, body mass index and smoking.

"What we know from the data we have, and it’s not great data, is that transdermal estradiol [patches] is the safest way to take it," said Dr. Megan Lochner, an obstetrician-gynecologist at Stony Brook Medicine. "We know that oral estradiol [estrogen] gets metabolized by your liver, so it can affect your liver and does slightly increase your risk of blood clots."

Lochner said it’s important to look at each patient's individual symptoms and health when deciding whether or not to prescribe hormones.

"As a clinician, I don't think [this study] changes how I would counsel patients," said Lochner, who specializes in hormone therapy as well as nonhormonal treatments for the symptoms of perimenopause and menopause. "I think it backs up the way I'm already counseling them."

Menopause hormone therapy has had a resurgence in recent years as women speak more openly about their symptoms and seek relief. There has also been a change in how hormone therapy is viewed.

A 2002 study, part of a large research initiative, concluded that the risks of breast cancer, coronary heart disease and blood clots outweighed the benefits of menopause hormone therapy. Doctors were dissuaded from prescribing it, and women were afraid to ask for it.

Newer research has found limitations in that study, and last year the U.S. Food and Drug Administration removed the "black box" warning on these medications.

The number of women seeking menopause hormone therapy has boomed, causing a shortage of some of the patches.

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.