Menopause, Heart Disease, and Benefits of Hormone Therapy

Key takeaways

• Be aware of the connection between menopause and heart health. Your risk of heart disease increases after the menopause transition due to changes in hormones and metabolism.
• Understand how hormone therapy works. It replaces some of the hormones your body stops producing when you go through menopause, which can prevent or treat common symptoms like hot flashes and night sweats.
• Know that hormone therapy is a safe treatment for certain people. Providers don’t prescribe hormone therapy for the sole purpose of preventing heart disease, but it can be a good option for women who are less than 10 years post-menopause and have no history of heart attacks or strokes.
• Talk with your doctor to see if hormone therapy is right for you. Hormone therapy is safe for women with heart disease risk factors like high blood pressure, high cholesterol, or obesity if started within 10 years of the menopause transition.
• Stay informed about ongoing research at Mass General Brigham. Our researchers continue to study what drives heart disease in women, such as how menopause-related hot flashes affect heart health, and their findings can provide valuable information for managing your well-being.

Menopause is a natural and normal part of the aging process, and all women experience it during their midlife. Periods become irregular and eventually stop. Women are no longer able to get pregnant as a result.

During this time, the hormones that control the menstrual cycle undergo large shifts. In turn, many women experience physical symptoms, including ones you may have heard of, like hot flashes. What many people may not know is that these hormonal changes can also affect the body in other, less obvious ways, like increasing the risk of heart disease.

“Midlife women are thought to be at low risk for heart disease, because many of our risk calculators only capture 10-year risk of cardiovascular disease,” says Emily Lau, MD, MPH, a Mass General Brigham Heart and Vascular Institute cardiologist and researcher. “While it’s true that many of our midlife patients have a low risk of developing heart disease over the next 10 years, I don’t just want my patients to be free of heart disease for the next 10 years. I want them to live their whole lives without heart disease.”

Dr. Lau is the co-director of the Women’s Heart Health Program at Mass General Brigham, where she cares for patients with a focus on cardiovascular health across the lifespan. In this article, Dr. Lau explains what we know about the cardiovascular effects of menopausal hormone therapy (HT), how it can help relieve common menopause symptoms, and why it can be a safe treatment option for many women when started at the right time and in the right clinical context.

Heart disease and menopausal hormone therapy (formerly hormone replacement therapy)

For decades, there was confusion about the relationship between heart disease and menopausal hormone therapy (HT), formerly called hormone replacement therapy. At different times, people thought that HT could help prevent heart disease, or that it could increase cardiovascular risk. The reality is more nuanced.

“Women are often busy taking care of their families, aging parents, and careers. This is a window of opportunity for us to ensure that we are optimizing cardiovascular risk factors in our midlife women patients, so that we can prevent them from developing heart disease down the line,” she says.

Why does menopause increase risk of heart disease?

Menopause causes metabolic changes that can put women at a greater risk for heart disease. These include:

• High blood pressure or hypertension
• Higher levels of cholesterol
• Slower metabolism
• Changes in weight distribution, including an increase in visceral fat. “That type of fat is known to be more harmful to our cardiovascular system,” says Dr. Lau.

These risk factors can put postmenopausal women at greater risk of heart attacks, coronary artery disease, and stroke.

“After the menopause transition, a woman’s risk of heart disease rises significantly. Before menopause, women have much lower rates of cardiovascular disease than men. And during menopause, we see that risk really start to accelerate,” Dr. Lau says.

For years, it was thought that estrogen was responsible for these changes. “We know that estrogen produced naturally in the body has a lot of good effects on the cardiovascular system. It reduces damage to cells and lowers blood pressure,” explains Dr. Lau. “After menopause, women have much lower levels of estrogen, so this was thought to be the driver of these changes in cardiac risk factors.”

In 1991, the National Heart, Lung and Blood Institute began a large clinical study called the Women’s Health Initiative (WHI). The study focused on how to prevent heart disease, breast and colorectal cancer, and osteoporosis in postmenopausal women. As part of the trial, clinicians gave postmenopausal women high doses of estrogen.

“They found that not only did treatment with estrogen not improve heart health or reduce cardiovascular events, it even, surprisingly, increased these events,” Dr. Lau says.

Prescriptions for hormone therapy, or HT, plummeted after the Women’s Health Initiative study was published. However, secondary analyses conducted after the trial have shown that the cardiovascular effects of HT depend on a woman’s age, timing since menopause, and underlying health. For many appropriately selected women, particularly those who begin treatment around the time of menopause, HT can be a safe and effective treatment for menopausal symptoms.

Hormone therapy for menopause signs and symptoms

The average age of menopause in the United States is 52, according to the National Institute on Aging (NIA). Most women begin transitioning into menopause between the ages of 45 and 55. This transition period, known as perimenopause, can last for several years. Once a woman goes a full year without a period or spotting, she’s officially reached menopause. Some women may go through menopause early due to health conditions like polyendocrine metabolic ovarian syndrome (PMOS, formerly called PCOS) or primary ovarian insufficiency, or if the ovaries need to be surgically removed.

“The primary hormonal change that we see with menopause is a drop in estrogen levels,” says Dr. Lau.

During menopause, the ovaries also reduce the production of the hormone progesterone. While both men and women’s bodies produce estrogen and progesterone, in women the hormones play key roles in sexual development, reproductive health, and pregnancy.

These lower hormone levels can result in signs and symptoms like:

• Hot flashes
• Night sweats
• Problems with sleep
• Vaginal dryness and other sexual changes
• Mental health challenges like depression or anxiety
• Fatigue or brain fog
• Changes in body composition or gaining weight
• Bone density loss, known as osteoporosis

“Hot flashes and night sweats are the most common symptoms of menopause. It affects up to 80% of women. Some women can have very, very significant and severe hot flashes to the point that it interferes with their daily lives,” Dr. Lau says.

Benefits of hormone therapy for women with menopause symptoms

Menopausal hormone therapy, also known as HT and formerly called hormone replacement therapy, replaces some of the hormones your body no longer makes after you go through menopause. This may help with some symptoms related to menopause. According to the American College of Obstetricians and Gynecologists (ACOG), there are two main types of hormone therapy:

1. Estrogen therapy
2. Combined hormone therapy, which includes both estrogen and progesterone

Depending on the symptoms being treated, clinicians can prescribe HT in a variety of different ways, including:

• Oral tablets
• Skin patches
• Gels
• Sprays
• Vaginal rings, tablets, or gels

What are the signs that you need hormone therapy for menopause?

Dr. Lau notes that the Food and Drug Administration (FDA) has approved HT to prevent or treat the following conditions related to menopause:

• Hot flashes and night sweats
• Bone loss
• Premature menopause (starting before age 40)
• Severe vulvovaginal atrophy (thinning or drying of the vaginal walls)

“The large majority of women, perimenopausal and postmenopausal, have hot flashes, night sweats, and bone loss. All of these are important indications, and there is a role for hormone therapy in the right population,” Dr. Lau says.

Is menopausal hormone therapy safe?

Dr. Lau began the Cardiometabolic Hormones and Health Clinic at Mass General Brigham to meet the needs of midlife women. “I consult with patients and their care team, like primary care providers (PCPs) or general cardiologists, to determine if it’s safe for the heart to start hormone therapy,” she says.

The more recent findings from the WHI study have shown that HT is safest if started less than 10 years post-menopause.

Even though hormone therapy isn’t prescribed solely for the prevention of heart disease, it can be safely prescribed for younger, recently post-menopausal women with heart disease risk factors.

“We do not recommend hormone therapy for women who have a history of heart attack, stroke, or other cardiovascular event,” Dr. Lau explains. For those women, hormone therapy is associated with a higher risk of further heart problems. “But for women who might be at a greater risk of heart disease, with obesity, high blood pressure, or high cholesterol, it’s safe for them to be on hormone therapy if they are less than 10 years post-menopause.”

The latest research on women and heart disease

Dr. Lau and her research group investigate what drives cardiovascular disease in women.

In one recent study, they found heart disease risk may vary among women who use hormonal contraception. Most women, including those with depression or anxiety, had a lower risk of major adverse cardiovascular events, but women with post-traumatic stress disorder (PTSD) didn’t have that lower risk. Stress increases risk of heart disease, and this study points to future research on how hormonal birth control (contraceptives) may affect heart disease risk in women, especially in those with stress-related mental health conditions.

Menopause-related hot flashes and heart health

“We also have an ongoing, patient-oriented study at Mass General called FLASH-CV that is examining how menopause-related hot flashes may affect cardiovascular health,” Dr. Lau explains. “We know that the menopause transition is accompanied by important changes in cholesterol, inflammation, blood vessels, and metabolism, but we still have a lot to learn about how menopause-related symptoms, like hot flashes, may influence heart health.”

In FLASH-CV, Dr. Lau and her team study women with bothersome menopausal symptoms to understand if that affects cardiovascular health by measuring changes in blood vessel function, cholesterol, inflammation, and other cardiovascular markers. They also use advanced cardiac imaging to assess blood flow through the heart’s small blood vessels.

“One of the questions that we are trying to answer is whether treating hot flashes also has effects on cardiovascular health,” Dr. Lau says. “By looking at blood vessel function, inflammation, cholesterol, and other markers, we hope to better understand how menopause and its treatments may affect a woman’s heart health.”

More research needed

Ultimately, there’s more work to needed to prevent cardiovascular disease in postmenopausal women. “Estrogen probably explains some of it, but there are more complex physiological changes that we don’t yet fully understand. That’s an area that I think needs a lot more investigation, and is something I’m very passionate about studying,” says Dr. Lau. “This is a real opportunity for us to improve the health of our women patients.”