Hormone replacement therapy (HRT) dramatically increases the risk of heart disease within two years of a woman starting the drug, new research has confirmed. Combined HRT - which includes both estrogen and progestin - doubles the risk of heart disease, the major Women's Health Initiative has concluded. The risk remains the same for all women of any age, provided they started HRT therapy within 10 years after menopause. Overall, combination HRT doubles the risk for stroke and dangerous blood clots, and women are being urged to discuss these very real dangers with their doctors before beginning treatment, say researchers from the National Heart, Lung and Blood Institute. Earlier studies have confirmed that combined HRT also increases the risk for breast cancer. (Source: Annals of Internal Medicine, 2010; 152: 211-7).