Postmenopausal women without previous or current vasomotor symptoms do not flush after abruptly abandoning estrogen replacement therapy

Most but not all women suffer from vasomotor symptoms around menopause. The exact mechanisms behind these symptoms are unknown, but the rate of decline in estrogen concentrations has been suggested to affect the risk of hot flushes.

The objective was to assess whether vasomotor symptoms were induced in women without previous such symptoms, when the women were given combined estradiol and progestagen therapy for 3 months, whereafter therapy was abruptly withdrawn.

After randomization, 40 postmenopausal women without previous or current vasomotor symptoms were treated transdermally with either 50 micrograms/day 17 beta-estradiol or placebo during 14 weeks. During the 13th and 14th weeks, treatment was combined with oral medroxyprogesterone acetate 10 mg/day. Serum estradiol and follicle-stimulating hormone (FSH) concentrations were analysed before and after 12 weeks of therapy. Climacteric symptoms were assessed at the same intervals as well as 8 weeks after the end of therapy.

All women had low pretreatment levels of estradiol and high FSH concentrations. During estradiol therapy estradiol levels increased significantly, whereas FSH only decreased slightly. No woman developed vasomotor symptoms after withdrawal of therapy.

Postmenopausal women without previous or current vasomotor symptoms did not develop such symptoms when estrogen replacement therapy was first instituted and then abruptly stopped. Probably other factors than the rate with which estrogen concentrations decrease determine whether or not a woman will develop vasomotor symptoms. Evidently, estrogens can be prescribed to a woman who has no vasomotor symptoms, without much risk of inducing such symptoms if she decides to abandon therapy, even after 3 months of treatment.