There’s an excellent article by Cynthia Gorney in the New York Times on the possible risks and benefits of estrogen therapy, in particular for women in perimenopause (the year following a final period). I’ve written about the effects of estrogen regarding birth-control pills, but supplemental estrogen as it relates to menopause introduces a new–and possibly game-changing–element to my general hormone-therapy wariness.

In her article, Gorney explains why estrogen therapy has been so widely feared for the last ten or so years, with the Women’s Health Initiative–a federally funded study that began in the early 1990s and ended in 2002 when researchers agreed the hormone trials were too dangerous to continue–at the middle of the fray. She goes on to explain that the study’s conclusions were taken out of context, citing “fine print” about the drugs used in the study.

First of all, the kind of estrogen in my patches–there are different forms of estrogenic molecules–is called estradiol. It’s not the estrogen used in the W.H.I. study. Pharmaceutical estradiol like mine comes from plants whose molecules have been tweaked in labs until they are atom for atom identical to human estradiol, the most prominent of the estrogens premenopausal women produce naturally on their own. The W.H.I. estrogen, by contrast, was a concentrated soup of a pill that is manufactured from the urine of pregnant mares. The drug company Wyeth (now owned by Pfizer) sells it in two patented products, the pills Premarin and Prempro, and it’s commonly referred to as “conjugated equine estrogens.”

I was curious: just how fine was that print when the W.H.I. was shut down in 2002? A press release issued at the time by Wake Forest University Baptist Medical Center, one of the institutions involved in the studies, read:

The study’s Data and Safety Monitoring Board found that the risks of taking the combination [of estrogen and progestin]–0.625 milligrams a day of conjugated equine estrogens plus 2.5 milligrams per day of medroxyprogesterone–now exceed the benefits. “Compared to those taking placebo, more women taking active estrogen plus progestin developed breast cancer or experienced cardiovascular events such as heart attacks, strokes, pulmonary emboli and deep vein thromboses.”

The study was testing this estrogen-progestin combination because 7 million women in the United States take this same combination daily. One trade name for it is Prempro.

So we knew in 2002 that equine estrogens specifically were used in the W.H.I. studies, and we reported that information in places as obvious as university press releases. And only now, a decade later, are researchers undertaking the staggering task of re-educating millions of women on the dangers of a treatment that might not be as dangerous as we thought.