Estrogen therapy is also characterized by several side effects and some of them have severe risk. Estrogen causes the internal lining of the uterus to become thick giving rise to condition known as endometrial hyperplasia which can develop into cancer if not treated. Prolonged exposure to estrogen therapy can lead to risk of endometrial cancer.

High estrogen doses are also linked to increase in the risk of heart attack and clotting of blood. If the women are undergoing estrogen therapy, then cigarette smoking can lead to clotting of blood and smoking also reduces the effect of estrogen therapy. Confusion, increase in the weight, increase in the size of the breast, pain in breast are some of the side effects that are associated with estrogen therapy. Some other side effects are nausea, vomiting feeling, swelling of ankles and knees, irritation and redness of the skin with development of skin rashes.

If estrogen therapy is used for long time, then the chance of breast and uterine cancer increases. Since after menopause, estrogen level in the body reduces and to supplement it, women take estrogen therapy but it can lead to gallbladder disease. Some of the rare side effects of estrogen therapy are urine passage which is not under your control, depression and dizziness.