Hormone Replacement Therapy and Osteoporosis

Hormone replacement therapy (HRT) and estrogen replacement therapy (ERT) were initially indicated for treatment of the symptoms of menopause, but they are now approved for both prevention and treatment of postmenopausal osteoporosis. This is because declining estrogen and progesterone levels do not just affect a woman's reproductive capabilities; they also cause bone density to decrease and the risk of fractures to increase. By taking estrogen either as ERT or as HRT, bone loss can be slowed and bone density can even be regained.

Estrogen replacement therapy versus hormone replacement therapy

ERT is available in a variety of forms, such as oral tablets or topical patches applied to the skin, and can be made from a mixture of different naturally occurring estrogens or from a single type of estrogen. ERT only replaces the estrogen that stops being produced by the body during menopause. Estrogen therapy taken alone (ERT or unopposed estrogen) can increase a woman’s risk of developing cancer in the uterus (cancer of the uterine lining, called endometrial cancer).

For women who have not had their uterus removed (have not had a hysterectomy), doctors prescribe an additional hormone called progesterone, or a synthetic version called progestin. Progesterone in combination with estrogen is called HRT. HRT works by replacing both estrogen and progesterone levels to mimic the levels that were in effect before menopause, and it reduces or eliminates the risk of endometrial cancer in women who have not had a hysterectomy.

Why do women need progesterone?

Unlike ERT (estrogen alone), HRT is a combination of estrogen and progesterone. The progesterone in HRT is important because it prevents the unchecked growth and buildup of the uterine lining (which occurs when only estrogen is used), and this greatly reduces, and may even eliminate, the increased risk of uterine cancer seen in women who take estrogen alone or unopposed by progestin. Therefore, women who have a uterus (have not undergone a hysterectomy) should be prescribed HRT rather than ERT.

Hormone replacement therapy, estrogen replacement therapy, and hysterectomy

Doctors perform a hysterectomy to treat conditions that involve the uterus, such as severe endometriosis, uterine or ovarian cancer, or persistent uterine fibroids. A hysterectomy is a kind of surgery that involves removing the uterus. In women who have not had a hysterectomy, HRT is recommended because estrogen alone (ERT) increases the risk of uterine cancer. If a woman has had a hysterectomy, and in some cases if she is only going to be taking estrogen for a short period of time (less than a year), her doctor may prescribe ERT. A woman should talk to her doctor about HRT and ERT.

Side effects of hormone replacement therapy

Like any medication, HRT can cause a number of unwanted side effects. Fortunately, most side effects are rare, and even the more common ones tend to disappear after the body adjusts to the hormones.

A woman should always note how she feels after taking a new medication. In general, she should consider calling the doctor if she experiences something that is severe; is moderately painful or uncomfortable and does not seem to be going away; or is mild, yet noticeable, and lasts for an extended period of time. If she does not feel right after taking a new medication, she should let the doctor know.

The long-term effects of HRT are being studied, and new information is becoming available. Doctors are now recognizing that lower doses are likely to be effective and that lower doses seem to significantly reduce the likelihood of side effects. Because HRT is a combination of 2 different hormones (estrogen and progesterone), the side effects a woman can experience may be caused by either one, or by a combination of both. Some doctors give the estrogen and progesterone as 2 separate supplements rather than as a combination pill in order to facilitate the adjustment of one or the other to minimize side effects. Sometimes using different forms of the compounds, such as a cream or a patch applied to the skin instead of a pill, can also reduce side effects. Keep in mind that a mild side effect may just be a sign that the body is getting used to something new.

Side effects of estrogen

• Common nonemergency side effects of estrogen - Although they are not considered emergencies, talk to the doctor as soon as possible if any of the following are experienced:
  
  
  • Breast discomfort
  
  
  
  • Breast swelling or increased breast size
  
  
  
  • Bilateral swelling of the legs and feet (swelling on both the right and left sides of the body)
  
  
  
  • Rapid weight gain
     
• Urgent side effects of estrogen - Call a doctor immediately if any of the following side effects are experienced and they don't go away or they become more severe:
  
  
  • Stomach bloating or cramps
  
  
  
  • Decreased appetite
  
  
  
  • Nausea; vomiting; fever; or pain, swelling, or tenderness in the upper right abdomen may indicate gall bladder toxicity
  
  
  
  • Prolonged or persistent vaginal bleeding or spotting
  
  
  
  • Breast lumps or discharge
  
  
  
  • Abdominal pain (may indicate liver or gall bladder toxicity)
  
  
  
  • Yellow skin or eyes (may indicate liver toxicity)
  
  
  
  • Calf pain and/or swelling (may indicate a blood clot)
  
  
  
  • Chest pain or shortness of breath
  
  
  
  • Mild diarrhea
  
  
  
  • Mild dizziness
  
  
  
  • Mild headache or migraine
  
  
  
  • Difficulty with contact lenses (lens prescription needs adjustment)
  
  
  
  • Increased sexual desire
  
  
  
  • Occasional vomiting

Side effects of progestin

• Emergency side effects - Call the doctor immediately if any of the following side effects are experienced:
  
  
  • Difficulty breathing
  
  
  
  • Severe headache
  
  
  
  • Change or loss of vision
  
  
  
  • Severe depression
  
  
  
  • Dizziness
  
  
  
  • Weakness or numbness in an arm or leg
  
  
  
  • Calf pain and/or swelling (may indicate a blood clot)
  
  
  
  • Chest pain
  
  
  
  • Unexplained coughing or coughing blood
  
  
  
  • Yellow skin or eyes
     

• Less urgent side effects - Call the doctor if any of the following side effects become severe or simply don't seem to be going away:

  • Breakthrough bleeding between menstrual periods
  
  
  
  • Noticeable changes in menstruation
  
  
  
  • Absent menstruation
  
  
  
  • Bloating
  
  
  
  • Noticeable weight changes
  
  
  
  • Darkening patches of skin
  
  
  
  • Acne
  
  
  
  • Fatigue
  
  
  
  • Indigestion
  
  
  
  • Breast pain