Women who suffer from severe menopausal symptoms such as hot flashes and night sweats often turn to hormone replacement therapy for relief, despite potential risks. Now, new research shows that some forms of HRT may cause hearing loss.

An HRT regimen for postmenopausal women that included progestin was linked to greater hearing loss than that experienced by women who either took estrogen alone or no hormones at all in a recent study published in the Proceedings of the National Academy of Sciences.

Senior author Robert D. Frisina of the University of Rochester Medical School and colleagues evaluated 124 women who were 60 to 86 years old. All of the women were in good health and had undergone multiple hearing tests.

The researchers assigned the women to one of three groups: those who took estrogen and progestin, those who took estrogen alone, and those who took no replacement hormones.

The study participants who took estrogen and progestin fared worse in speech perception capabilities than those in the other two groups. The researchers concluded that the changes were related both to inner ear function and brain function, because the problems were experienced in quiet environments as well as with substantial background noise. The women were able to notice the changes themselves, Frisina said.

The researchers were unable to determine the cause for the apparent effect.

Hearing loss is just the latest addition to a long list of negative side-effects associated with HRT, including greater risk of breast cancer, heart attacks, strokes and dementia.

Use of HRT should be reserved for the most severe menopausal symptoms, Frisina advises. Women who already have some hearing loss might want to approach HRT even more cautiously.

Age-related hearing problems are among the top three chronic health conditions in elderly people, the report notes, although the extent to which they are caused by environmental noise exposure as opposed to age, medical conditions or the use of HRT is unknown.