Treatment with progesterone, a naturally occurring hormone that has been shown to alleviate severe hot flashes and night sweats in post-menopausal women, poses little or no cardiovascular risk, according to a new study by the University of British Columbia and Vancouver Coastal Health.
Jerilynn Prior
The findings, published Jan. 15 in PLOS ONE, help to dispel a major impediment to widespread use of progesterone as a treatment for hot flashes and night sweats, said lead author Jerilynn C. Prior, a Professor of Endocrinology and the head of Centre for Menstrual Cycle and Ovulation Research.
For decades, women used a combination of synthetic estrogen and progesterone to reduce the frequency and severity of hot flashes and night sweats, caused by dramatic and unpredictable fluctuations of estrogen, usually during perimenopause (the years leading up to and a year beyond the final menstrual cycle). Those symptoms usually continue into postmenopause.
Estrogen was considered the active ingredient in this so-called “hormone replacement therapy,” which was also considered effective in preventing osteoporosis and keeping women looking younger and more feminine. Progesterone was included mostly to guard against a thickening of the endometrium, the lining of the uterus, which could lead to uterine cancer. (Women whose uteruses had been removed by hysterectomy are usually given estrogen alone.)
This combination hormone therapy fell off dramatically after 2002, when a large study revealed that it increased risk of heart disease, breast cancer, strokes and other serious conditions. Though doctors still prescribe short-term estrogen for women with severe night sweats and hot flashes, it’s not considered safe as a long-term prevention against osteoporosis or any other conditions of aging. Since estrogen use began to decline, breast cancer rates have started to fall; health statisticians believe the two trends are linked.
Dr. Prior, a professor of endocrinology, has long believed that progesterone could safely alleviate the symptoms but without the same risk. So she and her collaborators recruited 110 healthy Vancouver-area women who had recently reached postmenopause (a year after the final menstruation), giving half of them oral progesterone and the others a placebo.
The three-month study used each woman’s age and changes in their blood pressure and cholesterol levels to calculate their 10-year risk of a heart attack and other blood vessel diseases, and found no difference between those taking progesterone and the control group. The study also found no significant difference on most other markers for cardiovascular disease.
“Many women are apprehensive about taking progesterone for hot flashes because of a belief that it carries the same risks, or even greater risks, than estrogen,” Dr. Prior says. “We have already shown that the benefits of progesterone alone have been overlooked. This study demonstrates that progesterone’s risks have been overblown.”
Dr. Prior, in contrast to many of her colleagues, has been prescribing progesterone since it became available in Canada in 1995, for postmenopausal women to treat flashes and night sweats, and for peri-menopausal women to alleviate hot flashes, heavy menstrual flow and sore breasts. In a randomized controlled study published in 2012, Dr. Prior and research associate, Christine Hitchcock, showed that progesterone significantly reduced the intensity and frequency of night sweats and hot flashes, compared to a placebo, in postmenopausal women.
Dr. Prior is now recruiting Canadian women for a similar study examining progesterone’s effectiveness for treating perimenopausal night sweats and hot flashes. For more information, visit http://bit.ly/progesterone-study.