NEW YORK (Reuters Health) - The loss of estrogen that accompanies menopause contributes to the development of obesity and high blood pressure (hypertension), according to studies conducted in female rats.Estrogen is known to protect women against heart disease. When women reach menopause, their estrogen levels drop dramatically and they lose this protection and often put on weight Dr. Lourdes A. Fortepiani of the University of Texas Health Science Center at San Antonio, reported.