- Among the most common endocrine side effects are:
- break-through bleeding or spotting,
- loss of periods or excessively prolonged periods,
- breast pain,
- breast enlargement, and
- changes in sexuality (increase or decrease in libido).
- Abdominal pain may indicate the development of gallstones or occasionally hepatitis.
- Migraine headaches have been associated with estrogen therapy.
- Estrogens can cause sodium and fluid retention leading to edema.
- Melasma, tan or brown patches, may develop on the forehead, cheeks, or temples. These may persist even after the estrogen is stopped.
- Conjugated estrogens may cause an increase in the curvature of the cornea. Patients with contact lenses may develop intolerance to their lenses.
- Blood clots are an occasional but serious adverse effect and are dose-related. (The higher the dose of estradiol, the more likely blood clots are to form.) Cigarette smokers are at a higher risk for clots, and, therefore, patients requiring estrogen therapy are strongly encouraged to quit smoking.
- Estrogens can increase the risk of endometrial cancer. This risk may be decreased if estrogens are combined with progestin.
- Some people also have a higher chance of developing breast cancer while taking estrogens. Sometimes people who have breast cancer when they are taking estrogens may have increased calcium in the blood. If this happens, the estrogen should be stopped.
Quick GuideWhat to Expect During Menopause as You Age
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