NEW YORK (Reuters Health) – Progesterone capsules might be an alternative therapy for menopausal women who don’t want to use estrogen-based treatments for their vasomotor symptoms, said the lead investigator on a new randomized trial.
Dr. Christine Hitchcock from the University of British Columbia told Reuters Health, “There are certainly some people for whom estrogen is not an appropriate therapy and other people who wish to avoid it for other reasons. And progesterone offers a choice.”
Progesterone is typically thought of as an add-on to estrogen therapy to help prevent thickening of the uterus. It is approved by the Food and Drug Administration for that use, and for abnormal menstrual bleeding.
A few studies have looked at whether progesterone alone can also help relieve menopausal symptoms, but the findings have not been promising.
“The view is that progesterone has no effect on hot flushes,” said Dr. John Studd a gynecologist at Imperial College London who has studied progesterone and menopausal symptoms.
But Dr. Hitchcock said some physicians have seen benefits among their patients who were taking progesterone.
In their new trial, she and her colleagues gave 68 women three 100-mg capsules of micronized progesterone each evening for 12 weeks. They compared the number and severity of night sweats and hot flashes among these women to outcomes in 46 similar women who took a placebo instead.
For four weeks before taking the pills and during the three months of the study, the women recorded their symptoms.
The women who took progesterone started out experiencing an average of seven night sweats or hot flashes a day. At the end of the study they reported having three fewer episodes daily.
In comparison, women in the control group went from a little more than six episodes a day down to about four.
Similarly, on a scale from one to four, women on the hormone pills reported their symptoms to be 0.6 points less severe at the end of the study than at the beginning – down to 2.0 from 2.6.
In comparison, the placebo group reported their symptoms to be 0.4 points less severe at the end of the study – starting out at 2.4 and ending at 2.0.
Dr. Hitchcock said “it’s a bit of a mystery” as to how progesterone might be helping to ease women’s symptoms. One way might be to widen the temperature range at which the body feels comfortable.
Dr. Studd, who was not involved in this study, pointed out that progesterone acts as a tranquilizer, which is why the women in the study were given the hormone before bed.
“It will help sleep…and therefore they can sleep through their hot flushes and sweats,” he told Reuters Health. But the researchers don’t agree.
They distinguished daytime and nighttime symptoms, and found that women had about one fewer daytime hot flash after the hormone treatment compared with the placebo.
The researchers wrote in their study, published online March 26th in Menopause, that “the benefit of progesterone was not caused by improved sleep masking night sweats.”
Dr. Studd said a risk with progesterone is that women who experienced pre-menstrual irritability or depression in their younger years are at risk of triggering those symptoms while they’re on the hormone.
Two of the women who took progesterone in the study reported feeling depressed during the trial.
“The vast majority of people said that they had nothing (adverse) that they noticed,” Dr. Hitchcock said. She added that the study was not designed to evaluate the long term safety of the drug.
Her study was funded by donations from individuals and the hormone was donated by the company that makes it.
Dr. Studd, who is a proponent of estrogen-based hormone replacement therapy, remains skeptical that progesterone alone can relieve menopausal symptoms.