Menopausal hormone therapy was once the most commonly prescribed treatment in the United States. In the late 1990s, some 15 million women a year were receiving a prescription for it. But in 2002, a single study, its design imperfect, found links between hormone therapy and elevated health risks for women of all ages. Panic set in; in one year, the number of prescriptions plummeted. Hormone therapy carries risks, to be sure, as do many medications that people take to relieve serious discomfort, but dozens of studies since 2002 have provided reassurance that for healthy women under 60 whose hot flashes are troubling them, the benefits of taking hormones outweigh the risks. The treatment’s reputation, however, has never fully recovered, and the consequences have been wide-reaching. About 85 percent of women experience menopausal symptoms. Rebecca Thurston, a professor of psychiatry at the University of Pittsburgh who studies menopause, believes that, in general, menopausal women hav...