Estrace (Estrogen, Estradiol) has been reported to increase the chance of endometrial cancer in women who have been through menopause. This risk appears to depend on the length of time this drug is used and the amount of estrogen per dose. If you use this drug for an extended period, you should be evaluated at least every 6 months. If you experience abnormal vaginal bleeding, notify your doctor promptly. This medication is not effective in preventing or treating a tendency toward miscarriages nor the threat of miscarriage. This drug must not be used during pregnancy because its use may result in birth defects or cancer later in the child's life.This medication is a hormone and is given to women who no longer produce the proper amount. It is used to reduce menopause symptoms hot flashes, for osteoporosis, and treats certain cancers in both men and women.