Are there side effects from taking estrogen?

As with most medications and supplements, there are some risks associated with estrogen drug therapies. Estrogen is a hormone present in both females and males. After the onset of menopause, the amount of estrogen produced by the ovaries decreases, causing unpleasant symptoms in many women.

Who takes estrogen?

Estrogen is prescribed for a number of reasons, such as postmenopausal hot flashes and osteoporosis. Because estrogen increases the risk for endometrial cancer (cancer of the uterine lining), progestin is usually prescribed in conjunction with estrogen, unless the woman has had her uterus removed.

Most often, estrogen is given to postmenopausal women to treat menopausal symptoms. It has proven effective in treating hot flashes, vaginal dryness and itching, and it has been shown to reduce the risk of developing osteoporosis. Other reasons for taking estrogen include low estrogen production in younger women and breast or prostate cancer.

Possible Side Effects

Short-term Side Effects From Taking Estrogen

Short-term side effects of estrogen use include breast pain, hair loss, headaches, and unusual vaginal symptoms like bleeding, itchiness, redness, discharge and swelling. Estrogen may affect the gastrointestinal system, resulting in upset stomach, heartburn, gas, diarrhea, constipation, stomach cramps, nausea and vomiting. Tingling in the arms or legs, leg cramps and tight muscles may also be short-term problems. Additional side effects include nervousness, dizziness, depression, weight gain or loss, unusual hair growth, eye changes that affect contact lens users and an uneven darkening of the facial skin.

MedlinePlus, a service of the U.S. National Library of Medicine and the National Institutes of Health , says recipients of supplemental estrogen should call a doctor if they experience any of these possibly serious side effects: weakness or loss of appetite; hives, itching, rash or blisters; swollen or bulging eyes; sore throat, hoarseness or difficulty breathing or swallowing; difficulty controlling movements or joint pain; swollen face, tongue, throat, lower legs, arms, feet, ankles or hands; yellowed eyes or skin; tenderness or pain in the stomach; and fever, chills or other common signs of infection.

Long-term Side Effects From Taking Estrogen

The Women’s Health Initiative conducted a 15-year study of postmenopausal women to understand the group’s prevalent causes of death, disability and poor quality of life. Launched in 1991, the research project concluded in 2006 and included hormone therapy studies of estrogen taken alone (for women without a uterus) as well as estrogen taken with progestin.

The study found the long-term effects of taking estrogen are increased risk of heart attack, blood clots in the lungs or legs, breast cancer, strokes and dementia. This increased risk is rather small (for example, eight additional women out of 10,000 might have a stroke), and the U.S. Food and Drug Administration (FDA) has no plans to remove estrogen drug products from the market. There are also some concerns (unrelated to the study) that estrogen may increase the risk of developing ovarian cancer and gallbladder disease.

The FDA recommends that women discuss the possible side effects of estrogen therapy with their health care professionals before taking estrogen medication. According to the FDA, estrogen is still the most effective approved drug for treating hot flashes and significant vaginal atrophy in menopausal women. There are now other treatments available to offset the risk of developing osteoporosis and to treat vaginal dryness and itching. Essentially, estrogen should be taken at the lowest possible dose for the shortest possible duration to treat symptoms.

For articles related to the Women’s Health Initiative, look at its Web site. The FDA’s questions and answers about estrogen therapy can also be found on its Web page titled Center for Drug Evaluation and Research.