Endocrine Society 92nd Annual Meeting
SAN DIEGO — Healthy, normal-weight women within 10
years of their final menstrual flow may benefit from oral micronized
progesterone to reduce hot flushes and night sweats.
Results of an intent-to-treat analysis showed that women
assigned to progesterone experienced a 56% decrease in vasomotor symptoms
during 12 weeks of treatment compared with a 28% decrease among women assigned
Oral micronized progesterone may be an effective therapy
for treatment-seeking healthy women who do not want or should not take
estrogen, which is currently the only effective therapy for decreasing
vasomotor symptoms, according to Jerilynn C. Prior, MD, professor of
endocrinology and metabolism at University of British Columbia, Vancouver.
The randomized, masked, placebo-controlled trial
included 133 healthy, non-obese (mean BMI, 24.7) women with moderate to severe
vasomotor symptoms. The women were middle-aged (mean, 55 years), primarily
white (91%) and a mean 4.3 years had elapsed since last menstrual flow.
Prior and Christine Hitchcock, PhD, also from the
University of British Columbia, randomly assigned women to progesterone in a
300-mg dose (n=75) or identical placebo (n=58) before sleep each night for 12
weeks. Using data from self-recorded questionnaires, physical measurements and
fasting blood tests, the researchers determined the effectiveness of
progesterone on vasomotor symptoms.
“Progesterone was highly efficient, much more so
than placebo,” Prior said during the clinical trial symposium.
The primary outcome was vasomotor score, defined as the
average sum of women’s self-recorded intensity of vasomotor symptoms times
number each day during the last 28 days of therapy. The baseline vasomotor
score was 17, and women experienced a mean 6.8 symptoms per day.
Progesterone was also associated with a significantly
lower number of overall hot flushes and night sweats compared with placebo. The
researchers observed a 48% decrease among women assigned to progesterone vs. a
22% decrease with placebo.
The researchers reported no serious adverse events
associated with progesterone.
“This is the first evidence that oral micronized
progesterone, which is molecularly identical to the natural hormone, is
effective for women with symptomatic hot flashes,” Prior said in a press
The progesterone used in this study (Prometrium) is
manufactured from a steroid in yams, and is currently available only by
prescription in the United States and Canada.
According to Prior, the researchers have secured funding
for a randomized controlled trial of oral micronized progesterone on
perimenopausal vasomotor symptoms, an area for which there is currently no
evidence-based therapy. – by Matthew Brannon and Katie Kalvaitis
For practicing endocrinologists, it is very helpful to have information
regarding the effectiveness of this medication in reducing hot flashes. There
are obviously women who have contraindications to estrogen and in whom using
this typical pro-gestational agent, medroxyprogesterone acetate, is fraught
with side effects and metabolic abnormalities. It is not clear to me how the
researchers chose the dose of 300 mg, as opposed to other medications that are
available in the 100- or 200-mg doses. I also do not yet have a complete
understanding of when one might consider progesterone to be contraindicated.
But, having another option for our patients is important and I think that the
study was done well.
– Carol H. Wysham, MD
Assistant Clinical Professor of Medicine at the University
of Washington School of Medicine,
Section Head of the Department of
Endocrinology at Rockwood Clinic in Spokane, Wash.
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