I had a complete hysterectomy at age 46. I am interested in estrogen replacement, but I don't know whether I should use an oral formulation or a patch. What educational resources compare the pros and cons of each estrogen? I also have allergies, so I wish to completely investigate the additives.

--Sherry

Recent findings in large-scale research studies suggest that HRT may increase a woman's risk of breast cancer, heart disease and stroke. In addition, when estrogen is prescribed alone, it may increase the risk of ovarian cancer. Consult a physician before starting any medication regimen.

There is no one source that compares pros and cons of each type of estrogen replacement. In general, the benefits and disadvantages are the same for all estrogens, although side effects vary slightly with different forms. The effect of estrogen on a particular woman is highly variable, however; what works well for one individual may be completely wrong for her next-door neighbor or her sister.

Estrogen may be administered via pill, patch, vaginal cream, vaginal ring or injection. Compounding pharmacies can also make up estrogen skin creams and lozenges. There are several different types of estrogens -- and sources for that estrogen -- as well. The Physicians Desk Reference, a drug reference available at your local library, lists each brand of estrogen and the active ingredients.

There are some major differences between pills and the other forms of estrogens. Patches, creams and injections are all directly absorbed into the bloodstream, avoiding what is called the "first pass" effect that occurs when pills are digested and then metabolized in the liver. For this reason, forms other than oral are better for women with liver dysfunction. Also, many women who use these other forms of estrogen report less nausea compared to taking estrogen orally. There is also less of a harmful impact on triglyceride levels; a transdermal (through the skin) form of estrogen is preferred for women who have elevated triglycerides. Patches and injections are also more likely to keep estrogen levels steady, without the peaks and valleys that characterize any oral medication.

One downside of patches in particular is that some women are sensitive to the adhesive used and experience significant skin irritation. Some patches can be worn for an entire week and others that must be changed every three days. If irritation develops while using the one-week patch, changing to a three-day patch may be all that is necessary to alleviate this skin reaction.

There are many choices when it comes to estrogen replacement therapy. With good communication between woman and doctor, your therapy can be individualized to what works best for you.