There is increased interest in the use of a progesterone cream derived from plant sources as an alternative to conventional hormone replacement therapy in menopausal women. Leonetti and colleagues conducted a randomized, double-blind, placebo-controlled trial to assess the effectiveness of transdermal progesterone cream in relieving menopausal vasomotor symptoms and preventing bone loss.

The 102 postmenopausal women recruited for the one-year study were within five years of menopause, had not used hormonal products in the preceding year and had serum follicle-stimulating hormone (FSH) levels that indicated menopause. Assessment at the beginning of the study included history and physical examination, administration of a questionnaire for depression, measurement of bone mineral density of the lumbar spine and hip, and laboratory tests for cholesterol, low-and high-density lipoprotein, triglyceride and thyroid-stimulating hormone levels, as well as serum chemistry values. A lipid profile was obtained again at four months, and bone mineral density measurement, the complete battery of laboratory tests and depression screening were repeated at the end of the study. Each participant kept a symptom diary of the number of hot flashes.

Progesterone cream was given in a dosage of one quarter teaspoon daily (20 mg). The cream was massaged into the arms, breasts or thighs, and application sites were rotated on a regular basis. Compliance was checked by the amount of cream remaining at each clinic visit.

Forty-three women in the progesterone group and 47 in the placebo group completed the study. At the beginning of the study, vasomotor symptoms were reported by 30 of the women in the progesterone group and by 26 of the women in the placebo group. In the treatment group, 25 (83 percent) of the 30 women noted improvement or resolution of vasomotor symptoms. Conversely, only five (19 percent) of the 26 women in the placebo group reported improvement in vasomotor symptoms. Maximal improvement occurred during the first month of progesterone treatment. An increase in vasomotor symptoms was not reported by any of the women in the study.

Changes in the bone mineral density of the lumbar spine, femoral neck and total hip were similar in both groups. A small, insignificant decrease in the mean bone mineral density was noted in both groups. Lipid profiles were unaffected by progesterone therapy. Eight women in the progesterone group reported vaginal spotting, which resolved within two days.

The authors conclude that transdermal progesterone cream provides relief of menopausal vasomotor symptoms. While the study did not demonstrate an increase in bone mineral density, the authors note that the duration of treatment in their study and the progesterone dosage might have been a factor in the failure to show that progesterone cream prevents bone loss in postmenopausal women.

editor's note: Considering that a significant number of women now entering menopause have contraindications to estrogen replacement therapy or are unwilling to use it, progesterone may offer a means of symptom relief in women who cannot and will not take estrogen. The plant origin of the progesterone cream described in this study may have an appeal to some women, and use of a skin cream may be more acceptable to some women than tablets or depot injections. Women who use progesterone cream for menopausal symptoms must be made aware that the evidence of effects on bone mineral density and cardiovascular risk is contradictory. Not all hormone replacement therapies are equivalent, but many patients seem to believe that a regimen that relieves vasomotor symptoms also confers protection against cardiovascular disease and osteoporosis.—a.d.w.