What every woman should know about estrogen hormone therapy, which is associated with a reduced risk of cardiac failure and disease.

Estrogen hormone therapy in pill form may make women younger than 70 more likely to develop high blood pressure, according to a new study just published in Hypertension.

New research published today in Hypertension, a peer-reviewed American Heart Association journal, found that women 45 and older who took estrogen hormone therapy in pill form were more likely to get high blood pressure than those who used transdermal (applied to the skin) or vaginal forms.

According to the American Heart Association, after menopause, a woman’s body makes less estrogen and progesterone. These changes may increase the risk of heart disease and heart failure.

Menopausal women under the age of 60 or for whom menopause has occurred within the past ten years may benefit from some hormone therapies to lower their risk of cardiovascular disease, according to previous studies. Hormone therapy may be prescribed to relieve menopause symptoms, for gender-affirming care, and for contraception. While hypertension is a preventable risk factor for cardiovascular disease, the effects of various hormone therapies on postmenopausal women’s blood pressure are unclear, as the study’s authors point out.

“We know estrogens ingested orally are metabolized through the liver,” remarks lead author Cindy Kalenga, “and this is associated with an increase in factors that can lead to higher blood pressure.”

“We know that post-menopausal women have increased risk of high blood pressure when compared to pre-menopausal women, furthermore, previous studies have shown that specific types of hormone therapy have been associated with higher rates of heart disease,” Kalenga adds. “We chose to dive deeper into factors associated with hormone therapy, such as the route of administration (oral vs. non-oral) and type of estrogen, and how they may affect blood pressure.”

Does Estrogen hormone therapy really increase the risk of high blood pressure in women?

This research included nearly 112,000 women aged 45 and older who completed at least two consecutive prescriptions (a six-month cycle) for estrogen-only hormone treatment between 2008 and 2019, as determined by health administrative data in Alberta, Canada. The primary consequence of hypertension was identified using health records.

First, the researchers looked at the link between the method of estrogen-only hormone therapy delivery and the likelihood of acquiring high blood pressure at least one year after commencing the treatment. Oral, transdermal, and vaginal application were the three distinct routes of hormone therapy administration.

Researchers also looked at the potential for hypertension as well as the estrogen formulation that was being utilized. The researchers examined the medical files of people receiving estrogen-only hormone treatment for this study.

Estradiol, a synthetic estrogen that most closely resembles the estrogen produced by women’s bodies before menopause, and conjugated equine estrogen, the oldest form of estrogen therapy, were the two most popular forms of estrogen used by study participants.

The research revealed:

• Compared to women using transdermal estrogen, women receiving oral estrogen medication had a 14% greater risk of hypertension, while women using vaginal estrogen creams or suppositories had a 19% higher risk. After taking age into consideration, women under the age of 70 showed a greater correlation than women above the age of 70.
• In comparison to estradiol, conjugated equine estrogen was associated with an 8% higher risk of developing hypertension.
• The authors noted that taking estrogen for a longer duration or at a higher dose was associated with an increased risk of hypertension.

According to Kalenga, the study’s results imply that there are various forms of estrogen that may have fewer cardiovascular risks if menopausal women undergo hormone treatment.

“These may include low-dose, non-oral estrogen — like estradiol, in transdermal or vaginal forms — for the shortest possible time period, based on individual symptoms and the risk–benefit ratio,” Kalenga adds. “These may also be associated with the lowest risk of hypertension. Of course, this must be balanced with the important benefits of hormone therapy, which include treatment of common menopausal symptoms.”

Worldwide, women reach the natural menopause at a median age of roughly 50. According to the American Heart Association’s 2020 Statement on Menopause Transition and Cardiovascular Disease Risk: Implications for Timing of Early Prevention, there is current evidence that suggests beginning menopausal hormone therapy in the early stages may have cardiovascular benefits, but not in the late stages of menopause. Menopausal hormone treatment may help reduce menopause symptoms including hot flashes, nocturnal sweats, mood swings, or sleep issues, according to earlier research.

“Over a quarter of the world’s population of women are currently older than the age of 50. By 2025, it’s estimated that there will be one billion menopausal individuals on the planet,” explains co-author Sofia B. Ahmed.

“Approximately 80% of people going through menopause have symptoms, and for some it lasts up to seven years. While menopause is a normal part of the aging process, it has huge implications for quality of life, economic impact, work productivity and social relationships. We need to give people the information they need to choose the most effective and safe hormonal treatments for menopause.”

The research included a number of limitations. Only medical data were used to determine how various hormone treatment regimens affected outcomes for people with high blood pressure. The researchers utilized the beginning of estrogen medication in women over the age of 45 to signify postmenopausal status since the study excluded women under the age of 45 and did not gather information on hysterectomies or menopausal status. In contrast to women with an intact uterus, who may get a combination of estrogen and progestin, another kind of hormone, women who have had hysterectomy (the surgical removal of the uterus) are more often administered estrogen-only treatment. The authors emphasized that this indicates that these results may only be taken into account for women on estrogen-only hormone treatment. The results of the research also do not provide conclusive details about other groups, such as those with intact uteruses or premature or early menopause, that could gain advantages from estrogen hormone treatment.

Canadian women, who may have unique characteristics, were analyzed in this study. But the rules that are in place now in Canada are the same as those in the United States from the American College of Obstetricians and Gynecologists. Both highlight that hormone therapy should not be seen as a means of preventing or treating hypertension or heart disease and advise its usage in women with the proper conditions.

The authors will conduct additional research into the effects of combined estrogen and progestin formulations and progestin-only formulations of hormone therapy on cardiac and renal diseases.

Source: 10.1161/HYPERTENSIONAHA.122.19938

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