It is adapted to estrone. This is the most powerful estrogen produced by the ovary before menopausal stage. 3. Estriol - this is the least powerful among the three. Since these estrogen hormones can be taken, they have the same effects and side effects especially if the doses are the same. The hormones should not be used when a woman is pregnant because it can lead to miscarriage. This hormone is responsible for the regular menstrual period that usually occurs every 28 days. If your body is incapacitated of producing estrogen, you will experience menopause or the permanent cessation of menstruation. Old age is one of the major reasons why women experience such. However, a woman's body should continuously produce estrogen to maintain its sexual functions. It can give headaches or migraines 5. It increases the threat for endometrial cancer 6. It can destroy the liver With all these advantages and disadvantages presented, it all depends to the person if she wants to have the therapy. However, if you really want to take an estrogen therapy, it would be a nice idea if you discuss the matter carefully with your doctor. In this way, it can cause hair follicles to reduce in number and it can be the start of hair loss. The hair loss will stop once the hormones of the woman return to its normal state. Since hair loss is sometimes temporary in most women, it can be cured with shampoos that are intended to revert hair loss. Your body will find it difficult to maintain your natural anatomy. Low estrogen in the body also affects the normal function of the brain. There are many studies that tell that estrogen can prevent the existence of Alzheimer s disease. This is because estrogen increases the blood supply to the brain causing it to function well. A woman is advised to take an estrogen replacement therapy to improve the level of estrogen that decline due to a disorder called hysterectomy after the menopausal period. It is given for women who undergo either the premenopausal and postmenopausal period in their menstrual cycle. This is usually done in order to avoid possible discomfort and health problem brought by the imbalance estrogen hormone in the system of a woman.