Estrogen levels typically don't fall until late into menopause, and most perimenopausal symptoms -- irregular or heavy periods, moodiness, anxiety and nervousness or premenstrual migraines -- are caused by loss of progesterone. So estrogen replacement may not be needed until close to the end of menopause -- when a woman has gone a year without a period.
Symptoms of estrogen deficiency are hot flashes, night sweats, vaginal dryness, mental fuzziness, incontinence, decreased sexual response.
Estrogens
Estrogen is found in many medications: Premarin, most birth control pills and selective estrogen receptor modulators, or SERMs. There are also phytoestrogens, such as black cohosh or soy; and natural or biologically identical therapies made by compounding pharmacists.
The biggest selling product, Premarin, is made of estrogenic compounds derived from the urine of pregnant mares. It was introduced in 1942.
Estrogen is available in pills, skin patches and vaginal creams.
Progesterone
There are three sources of progesterone: synthetic, which includes Provera, norethindrone and norgestrel; plants, such as chasteberry and wild yam and bio-identicals, such as ProGest, Prometrium or Crinone, (vaginal gel).
Use of progesterone with estrogen replacement therapy provides a balance and prevents the increased risk of uterine cancer that accompanies use of estrogen without progesterone. Progesterone also can convert into other needed hormones, For example, if progesterone levels are sufficient, but testosterone is low, supplemental progesterone can transform itself into testosterone.
Prepackaged combinations of hormone replacement also are available. The most common is Prempro, a combination of Premarin and Provera, both synthetics. Others include Ortho-Prefest (combination of bio-identical estradiol and the synthetic progestin) and FemHRT, (a synthetic estradiol and synthetic norethindrone). Some women prefer these for convenience, although they can cause spotting for several months until their bodies adjust.
Testosterone
This is produced by the ovaries and adrenal glands. Deficiency of this hormone causes decreased libido, impaired sexual function, decreased energy and sense of well-being and thinning pubic hair.
Not all women's testosterone levels drop during perimenopause, and doctors should be careful before prescribing this. If there is no deficiency, supplementation can cause mood disturbances, acne, increased facial hair and deepened voice.
Selective estrogen receptor modulators, or SERMs
These are synthetic drugs -- known as designer estrogens -- such as tamoxifen and raloxifene. Raloxifene, marketed as Eli Lilly's Evista, promotes bone density while decreasing stimulation of breast tissue by estrogen.
Sources: "The Wisdom of Menopause," by Dr. Christiane Northrup, other sources.
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