It appears that women who take HRT may be at a slightly increased risk of breast cancer. This may be because some breast cancers grow faster with estrogen.
Endometrial cancer is cancer of the lining of the uterus.
Taking estrogen alone appears to increase the risk of this type of cancer. However, taking progestin along with estrogen greatly reduces this risk. The pill form of HRT may somewhat increase the risk of gallstones, stroke, blood clots and liver problems. Tell your doctor if you've had endometrial or breast cancer, liver or gallbladder disease, unexplained vaginal bleeding, a blood clot or a stroke. HRT may not be a good choice for women with these problems.