Objective To describe the prevalence of menopausal hormone therapy (HT) in 2008 and trends over the last 17 years in an Australian population.

Methods Data were obtained from nine representative population face-to-face interview surveys of the South Australian population from 1991 to 2008. The surveys used consistent method and quality control procedures. In 2008, demographic data, HT use and eight dimensions of health, using the SF-36 health survey questionnaire, were measured.

Participants Over 3000 South Australian adults were interviewed in their own home by trained health interviewers in each of the surveys; in the 2008 survey, 1555 women participated, of whom 953 were over age 40.

Results After a peak in use in the 2000 survey, HT use fell from 2003 and has continued to decline in 2008. In 2008, current use over age 50 of registered conventional HT products is now 11.8%, with a further 4.0% using non-registered alternative 'hormonal' products. Current HT use is highest between the ages of 50 and 59 years, where 13.4% use conventional HT and 7.7% use unconventional alternative hormones. Use of these unregistered hormonal products was rare in previous surveys. Median and mean length of conventional HT use were 10.0 and 10.5 years, respectively. HT users continued to have a demographic profile similar to those in previous surveys, i.e. they were better educated, employed, partnered, had a higher income and were less inclined to use complementary and alternative medicines.

Conclusions There has been a continuing decline in both the overall prevalence and length of use of conventional HT from 2003, probably in association with negative media about HT. Of medical concern is that about one-quarter of women using HT around menopause now chooses unregistered hormonal mixtures that are untested for long-term safety and efficacy.