Hormone therapy started in peri- or early post-menopause was linked to a 22 per cent lower risk of cardiovascular events in women with vasomotor symptoms in a recent study.

The findings came from an observational analysis of 20 years of health data and do not show that hormone therapy caused the reduction in cardiovascular risk.

The association was strongest among Black women and women who started treatment within 10 years of menopause onset, although researchers cautioned that the findings should not guide clinical practice.

The study is the first of its kind in the US to assess the risk of future cardiovascular events among women with vasomotor symptoms who use hormone therapy during peri- and early postmenopause.

Samar R. El Khoudary, professor and chair of the Department of Epidemiology at the VCU School of Public Health and one of the study’s senior researchers, said: “The menopause transition represents a critical window for understanding how hormone therapy may relate to cardiovascular disease risk. Our findings suggest that timing of initiation may influence cardiovascular outcomes.”

The researchers stressed that the findings do not support using hormone therapy to prevent cardiovascular disease.

Potential benefits must also be weighed against risks, including the increased breast cancer risk observed with longer-term use.

The study was not a randomised controlled trial, the gold-standard method for testing biomedical treatments.

Rebecca C. Thurston, associate dean for Women’s Health Research at the University of Pittsburgh School of Medicine and one of the study’s senior researchers, said: “These findings point to women with vasomotor symptoms as those who may show cardiovascular benefit from hormone therapy initiated during the perimenopause and postmenopausal years.

“However, conclusions should be tempered by the observational nature of the study, and findings should not guide clinical practice.”

Vasomotor symptoms, meaning hot flushes and night sweats, affect up to 80 per cent of women during the menopause transition and last for an average of seven to ten years.

Their frequency and severity build through perimenopause and typically peak in early postmenopause.

Hormone therapy replaces oestrogen and progesterone that women’s bodies stop producing after menopause and is currently the most effective treatment for these symptoms.

Clinical trials led by the Women’s Health Initiative in the early 2000s raised concerns about hormone therapy’s impact on heart disease, stroke, breast cancer and other risks, leading to years of reluctance among patients and providers to use the treatment.

El Khoudary said: “Hot flashes and night sweats have a significant impact on a woman’s quality of life and ability to work productively.

“While hormone therapy is an effective treatment for these symptoms, questions have remained about its cardiovascular effects, particularly the importance of when treatment is initiated during the menopause transition.”

More recent research suggests the effects of hormone therapy on the heart and vascular system may vary by age and treatment timing, with women younger than 60 who start treatment closer to menopause onset having different levels of risk.

In 2026, the US Food and Drug Administration removed “black box” warnings from hormone therapy products, reflecting evolving evidence on the benefits and risks of treatment.

Researchers from Virginia Commonwealth University and the University of Pittsburgh analysed data from more than 2,700 women taking part in the Study of Women’s Health Across the Nation (SWAN).

The women reported vasomotor symptoms and had not previously experienced cardiovascular events.

Clinical data collected between 1997 and 2017 were used to examine whether women who started hormone therapy for vasomotor symptoms were more or less likely to experience stroke, congestive heart failure, heart attack or revascularisation procedures than women who did not start treatment.

El Khoudary said: “By using data from the SWAN study, we essentially were able to emulate a series of hypothetical clinical trials to gain a deeper understanding into how hormone therapy taken to mitigate vasomotor symptoms during peri- and early postmenopause influences cardiovascular risk over time.

“It allowed us to examine clinically meaningful cardiovascular disease events over long-term follow-up in a population and treatment window that has been challenging to study prospectively.”

Starting hormone therapy during peri- or early postmenopause was associated with an estimated 22 per cent lower risk of cardiovascular disease events.

Women who began hormone therapy within 10 years of menopause onset had an estimated 27 per cent lower risk compared with women who did not start treatment.

Among Black women, starting therapy during peri- or early postmenopause was associated with an estimated 49 per cent lower risk of cardiovascular disease events.

No clear reduction was seen among women who started therapy more than 10 years after menopause onset or among White women and other racial and ethnic groups.

El Khoudary said: “The differences in cardiovascular outcomes by race and ethnicity are notable, particularly because Black women are more likely to experience severe vasomotor symptoms.

“These findings highlight the need to better understand how hormone therapy timing may influence cardiovascular outcomes across diverse populations.”

It remains unclear why cardiovascular risk differed according to when hormone therapy was started, although researchers believe differences in blood vessel health with age may play a role.

Weight loss surgery was linked to more regular periods and fewer polyendocrine metabolic ovarian syndrome (PMOS) symptoms in women aged 18 to 45 living with obesity in a recent study.

The researchers recommend that women undergoing the procedure have access to preconception care and reproductive counselling to support their reproductive health.

Researchers at the University of Surrey analysed data over 24 months from 84 women who underwent bariatric surgery and 18 women living with obesity who did not have surgery.

Of those who underwent surgery, 49 had gastric bypass procedures and 35 had gastric sleeve surgery.

Women who underwent metabolic bariatric surgery lost more than 30kg on average at 12 and 24 months after the procedure.

Among women with polycystic ovaries, the condition persisted in only 10 per cent after 24 months.

Women also reported a resolution of clinical hirsutism, or excess body hair, by 12 months.

Women who had previously experienced irregular periods reported more regular menstrual cycles after surgery.

Professor Martin Whyte, co-author of the study and professor of metabolic medicine at the University of Surrey, said: “A large proportion of those undergoing bariatric surgery are women of reproductive age, who may be planning a pregnancy in the coming years.

“So much remains unknown about the impact of this type of surgery on women who are planning to have children.

“This raises the question of when the ideal time after surgery is to conceive.”

Women have a higher prevalence of obesity than men, with 57 per cent of women in the UK classified as overweight and 27 per cent living with obesity, which can affect fertility and the health of an unborn baby.

The researchers said 17 women had healthy pregnancies following surgery.

Although this was not specifically examined in the study, no difference in birth weight was observed between babies conceived within or after the first year.

Dr Kathryn Hart, co-author of the study and associate professor in nutrition and dietetics at the University of Surrey, said: “What we have found is that bariatric surgery positively affects the reproductive health of women living with obesity and can improve the likelihood of them having a healthy pregnancy after surgery.

“Dysregulated hormone levels, irregular periods and conditions such as polycystic ovaries are affected by obesity.

“By reducing this, what we have seen is that it can lead to improvements without the need for medication.

“We would suggest that clinicians consider medical intervention for obesity to treat irregularities in the menstrual cycle and issues with fertility.”