Hormone Replacement Therapy (menopause) - History

History

The first clinical usage of hormone replacement therapy in the setting of menopause began in the 1950s, with the administered estrogen purified from the urine of pregnant mares. From that time until 1975, estrogen was administered without supplemental progesterone or progestin. A study from Kaiser Permanente by Dr. Harry Ziel demonstrated that in the absence of progesterone, patients were at increased risk of endometrial cancer with unopposed estrogen therapy. After this, progestin was supplemented in women who had not received surgicalhysterectomy, to reduce the incidence of endometrial hyperplasia and cancer. This was followed by the Women's Health Initiative (WHI) in 2002. However, the arm of the WHI receiving combined Estrogen and Progesterone therapy was closed prematurely by its Data Monitoring Committee (DMC) due to perceived health risks, although the trial arm was stopped only a full year after the data suggesting increased risk became manifest. In 2004, the arm of the WHI in which post-hysterectomy patients were being treated with estrogen alone was also closed by the DMC.