As with all medicines, there are risks and benefits. Scientists continue to study the long-term effects of HT. The most recent study found that Prempro, a type of menopausal HT, increased a woman's risk of blood clot and stroke, and slightly increased the risk of being diagnosed with breast cancer. Estrogen alone has not been shown to increase the risk of breast cancer. If you are concerned about taking menopausal HT, talk to your doctor; there are other options.