Progesterone Alone May Help Hot Flashes
Estrogen Alternative Needs More Study, Experts Say
June 22, 2010 -- Progesterone alone, when given in a form that's identical to the natural hormone, helps relieve the hot flashes and night sweats experienced by women during menopause, according to a new study.
The form of progesterone studied is known as oral micronized progesterone, says Jerilynn Prior, MD, professor of endocrinology and metabolism at the University of British Columbia, Vancouver, who presented her findings Monday at ENDO 2010, the annual meeting of The Endocrine Society, in San Diego.
''It's molecularly identical to what our own bodies make," she says of the progesterone studied. When she compared this progesterone for hot flashes to placebo, it came out on top. The regimen may prove to be a practical alternative to traditional hormone therapy, which combines progesterone and estrogen, the research suggests, especially for women who do not want to take estrogen or should not because of their medical history.
"Oral micronized progesterone is a highly effective treatment for hot flashes and night sweats," Prior says. The hormone is sold only by prescription and goes by the brand name Prometrium in the U.S. and Canada. It is synthesized from yams, and the micronization is meant to make it easier to absorb.
Progesterone for Hot Flashes: A Closer Look
Prior and her colleagues assigned 114 postmenopausal women who had hot flashes and night sweats to one of two groups. One group took 300 milligrams of Prometrium daily. The other took a placebo. Neither group knew whether they were taking Prometrium or the placebo.
The time since the last menstrual flow varied from one to 10 years and on average was four years. If the women had taken hormone therapy in the past, they had to have discontinued it for the past six months to be eligible to enter the study.
The women noted the number and intensity of symptoms in a daily diary, and then Prior calculated the average daily score that reflected the number and intensity of symptoms.
At the end of the 12-week study, Prior says, "Prometrium was significantly more effective than the placebo.''
The women taking Prometrium had a 56% decrease in their score, and the women taking the placebo had a 28% decrease.
The women taking Prometrium had a 48% decline in the number of symptoms; women taking the placebo had a 22% decline.
None of the women reported any serious adverse events, Prior says.
Exactly how progesterone relieves the symptoms isn't clear, Prior tells WebMD. "We know progesterone does lots of calming things in the brain. It may compensate for something estrogen does [to reduce the hot flashes]."