Women taking hormone pills to combat the symptoms of menopause may have increased risk of high blood pressure, a new study suggests.

A study found that oral oestrogen was associated with a 14% higher risk of high blood pressure compared with oestrogen creams, and a 19% greater risk of high blood pressure compared with vaginal oestrogen creams or suppositories.

The research in women aged 45 and older, also found that at the lowest dose, and for the shortest period of time, non-oral estradiol, a specific form of oestrogen, was linked with the lowest risk of developing high blood pressure.

According to the experts, oestrogen pills are processed through the liver, and this could be associated with an increase in factors that can lead to higher blood pressure.

It’s really important to have greater knowledge on safe and effective hormonal treatments for women during menopause

The findings suggest that if menopausal women take hormone therapy, there are different types of oestrogen that may have lower risks.

After menopause a woman’s body produces less oestrogen and progesterone, changes that may increase the risk of cardiovascular diseases including heart failure, heart disease and stroke.

Hormone therapy may be prescribed to relieve symptoms of menopause, in gender-affirming care and in contraception.

Previous research has found that some hormone therapies may reduce cardiovascular disease risk in menopausal women aged under 60, for whom it has been fewer than 10 years since menopause.

However, the potential effects of different types of hormone therapy on blood pressure in menopausal women remain uncertain.

Study lead author Cindy Kalenga, University of Calgary, Canada, said: “We know oestrogens ingested orally are metabolised through the liver, and this is associated with an increase in factors that can lead to higher blood pressure.”

She added: “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.

“We chose to dive deeper into factors associated with hormone therapy, such as the route of administration (oral vs. non-oral) and type of oestrogen, and how they may affect blood pressure.”

The study involved more than 112,000 women, who filled at least two consecutive prescriptions for oestrogen-only hormone therapy.

High blood pressure (hypertension) was identified via health records.

The researchers also found that taking oestrogen for a longer period of time or taking a higher dose was associated with greater risk of high blood pressure.

Study co-author Sofia Ahmed, a professor of medicine at the University of Calgary, said: “It’s really important to have greater knowledge on safe and effective hormonal treatments for women during menopause.

“At the end of the day, it’s an individualised decision about what is best for the person going through menopause and should include open dialogue with their physician or health care team.

“We need large, randomised studies factoring in all the complexities of hormone therapy around this important transition period in the female lifecycle.”

The findings are published in the journal Hypertension.