Hormone Replacement Risks and Benefits For Women

Benefits of Estrogen

Women who choose hormone replacement therapy do so because the side effects of hormone deficiency are unacceptable. These primarily include hot flashes (especially at night) and vulvo-vaginal changes (dryness and painful intercourse). In addition, some women experience mood changes and loss of libido, and for all of the above reasons, short term replacement of hormones is considered a medically reasonable decision by medical specialists. The American College of OB/GYN provides a balanced look at the indications and risks associated with hormone replacement therapy. Click here, for their review of hormone replacement therapy.

Long-term hormone therapy for the prevention of postmenopausal conditions is no longer routinely recommended. But women who take estrogen for short-term relief of menopausal symptoms may gain some protection against the following conditions:

  • Osteoporosis – Studies show that hormone therapy can prevent the bone loss that occurs after menopause, which decreases the risk of osteoporosis related hip fractures.
  • Colorectal cancer – Studies show that hormone therapy can decrease the risk of colorectal cancer.
  • Heart disease – Some data suggest that estrogen can decrease risk of heart disease when taken early in your postmenopausal years. A randomized, controlled clinical trial
  • The Kronos Early Estrogen Prevention Study (KEEPS) – exploring estrogen use and heart disease in younger postmenopausal women is under way, but it won’t be completed for several years. For the American College of OB/GYN opinion see this link.

Estrogen is still the gold standard for treating menopausal symptoms. The absolute risk to an individual woman taking hormone therapy is quite low – possibly low enough to be acceptable to you, depending on your symptoms.
The benefits of short-term hormone therapy may outweigh the risks if you:

  • Experience moderate to severe hot flashes or other menopausal symptoms.
  • Have lost bone mass and either aren’t able to tolerate other treatments or aren’t benefitting from other treatments.
  • Stopped having periods before age 40 (premature menopause) or lost normal function of your ovaries before age 40 (premature ovarian failure). This group of women has a different set of health risks compared to women who reach menopause near the average age of 50 including:
    • A lower risk of breast cancer
    • A higher risk of osteoporosis
    • A higher risk of coronary heart disease (CHD)

Benefits of Testosterone

Women normally produce small amounts of testosterone from the ovary and the adrenal gland, with most coming from the ovary. After natural menopause, and especially after surgical menopause (removal of ovaries), testosterone levels are lower than what is normally present. Some of the loss in energy during early menopause is related to the falling estrogen levels, but the degree of fatigue is also related to the fall in testosterone levels. Low testosterone can also lead to loss of muscle mass and increased fat deposition. Perhaps one of the most disconcerting symptoms of menopause can be the loss of libido. Since the primary sex organ is the brain, chronic diseases and stresses can severely impair the sex drive. Estrogen promotes vaginal health; while testosterone, just as in the male, promotes interest. Because the triggers for sex are multifactorial, studies that examine the effects of testosterone on libido have given mixed results. In men, the association is not debated and so most experts and most women patients do report a significant response to testosterone replacement. Testosterone has also been shown to be quite useful in the prevention and treatment of bone loss. It is probably more potent than estrogen in the management of osteoporosis.

Risks of Estrogen

The Women’s Health Initiative (WHI) is a long term national health study that focuses on strategies for preventing heart disease, breast and colorectal cancer, and fractures in postmenopausal women. This 15-year project involves over 161,000 women ages 50-79, and is one of the most definitive, far reaching programs of research on women’s health ever undertaken in the U.S. In this study, the combination hormone (conguated estrogen-progestin) Prempro, was studied along with estrogen alone (Premarin) compared to placebo to see if there was any cardiovascular protective effect and protection against osteoporosis. The combination arm of the study was terminated early because of the below findings, however the estrogen only arm continued.

According to the study, over one year, 10,000 women taking estrogen plus progestin might experience:

  • Seven more cases of heart disease than women taking a placebo
  • Eight more cases of breast cancer than women taking a placebo
  • Eight more cases of stroke than women taking a placebo
  • Eighteen more cases of blood clots than women taking a placebo
  • An increase in abnormal mammograms, particularly false positives

The study found no increased risk of breast cancer or heart disease among women taking estrogen without progestin. Over one year, however, 10,000 women taking estrogen alone might experience:

  • Twelve more cases of stroke than women taking a placebo
  • Six more cases of blood clots in the legs than women taking a placebo
  • An increase in mammography abnormalities

According to the WHI, women taking long term estrogen-progestin combination therapy have an increased risk of heart disease. A newer study published in the January/February 2006 issue of The Journal of Women’s Health suggests that these findings may be more relevant to women of more advanced age. This study also showed a decrease in the risk of heart disease when Hormone Replacement Therapy (HRT) was started in younger women (those just beginning menopause). Please keep in mind that these studies examine outcomes associated with oral medications that pass through the liver after absorption from the gastrointestinal tract. Oral medications are more likely to adversely affect clotting factors and lipid (cholesterol) levels which represent risk for the development of heart disease.

Important for women who undergo menopause naturally (i.e. uterus remains intact) estrogen is typically prescribed along with a progesterone derivative. This is because estrogen without progesterone can increase the risk of uterine cancer. Estrogen stimulates the lining of the womb (endometrium), regardless of the age, and the progesterone prevents an excessive buildup of this tissue. Unopposed estrogen (estrogen without progesterone) is unhealthy and represents an increased risk for endometrial cancer. Women who undergo menopause as the result of a hysterectomy can take estrogen alone.

Risks of Testosterone

The primary side effects associated with testosterone replacement are related to hormone sensitive tissues with testosterone receptors. This primarily involves the integument, or skin. There can be an increase in oiliness of the skin with a worsening of complexion. There can also be unwanted hair growth of the face, and even thinness of the hair of the scalp (extremely rare). All these are androgen (male) side effects which would be dose related. The goal of replacement is to restore levels to normal physiological levels. Monitoring the blood work minimizes these undesirable side effects. Remember these effects can also be seen in women who have a decrease in estrogen levels with menopause. Hormone replacement therapy with testosterone is always given with estrogen so that natural balance is preserved.

Who Shouldn’t Take Hormone Replacement Therapy?

Hormone replacement therapy is not usually recommended for women who have:

  • Active or past breast cancer
  • Recurrent or active endometrial cancer
  • Abnormal vaginal bleeding
  • Recurrent or active blood clots
  • History of stroke
  • Liver disease
  • Known or suspected pregnancy

Cigarette smokers should consider stopping tobacco use before taking HRT.

What Are the Side Effects of Hormone Replacement Therapy?

Like almost all medications, hormone replacement therapy has side effects. The most common side effects are:

  • Monthly bleeding
  • Irregular spotting
  • Breast tenderness

Less common side effects of HRT include:

  • Blood clots and stroke (rare, but the most serious risk).
  • Fluid retention
  • Headaches (including migraine)
  • Dizziness
  • Skin discoloration (brown or black patches)
  • Increased breast density making mammogram interpretation more difficult
  • Skin irritation under estrogen patch


  • The WHI was launched in 1991 and consisted of a set of clinical trials and an observational study, which together involved 161,808 generally healthy, postmenopausal women.
  • The clinical trials were designed to test the effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, and breast and colorectal cancer.
  • The hormone trial had two studies: the estrogen-plus-progestin study of women with a uterus and the estrogen-alone study of women without a uterus. (Women with a uterus were given progestin in combination with estrogen, a practice known to prevent endometrial cancer.) In both hormone therapy studies, women were randomly assigned to either the hormone medication being studied or to placebo. Those studies have now ended. The women in these studies are now participating in a follow-up phase, which will last until 2010.
  • Read more information on the study and findings at: Women’s Health Initiative – Home