Your doctor is misinformed. Synthetic forms of hormones are distinctly different molecules chemically. Bio-identical means it's the same as human hormones. There are many scientific studies documenting the danger from medroxyprogesterone and horse urine derived hormones. Estradiol is the most biologically active form of estrogen. Premarin is deprecated. Premarin does not contain estradiol and consists of is 50% estrone sulfate, 25% equilin, 15% eqilenin. Estradiol Valerate is actuality derived from Mexican yams by the pharmaceutical manufacturer.
My doctor, who is a woman and very well versed in HRT, is adamant about what she will prescribe. I'll stick with the real thing, thanks.
I reached the same conclusion (mainly reading "Screaming to be Heard" by Elizabeth Vliet Obgyn and finding an Obgyn who cared enough.) as Rascal.
Most of the participants who were in the infamous study that showed the high rate of heart diseases, strokes and breast cancers used Premarin, the urine-derived from a pregnant horse with a synthetic form of progestin (Provera).
Here is the breakdown of Premarin (synthetic horse urine-derived estrogen) according to Vliet (Rascal already mentioned, but I wanted to elaborate on one point...)
estrone 49.9%
equilin 22.8%
17-alpha dihydroequilin 13.5%
delta 8, 9 dehydroestrone 3.7%
17-alpha estradio 3.6%
equilenin 2.8%
17-beta dihydroequilinin 1.4%
17-alpha dihydroequilinin 1.4%
17-beta estradiol 0.5%
17-beta estradiol is the estrogen we stop producing after menopause, and Premarin only has 0.5% of that. The bio-identical HRT estradiol, on the other hand, is
100% 17-beta estradiol.
The estrone that Premarin contains (49.9%) is the predominant estrogen found in postmenopausal women and this form of estrogen are thought to be related to the higher risk of breast cancer in older women especially if they are obese. (Evidently, the fatter the woman, the more estrone is present in the body. I personally think a small amount of occasional progesterone to oppose the estrone may be a good idea. My former OBGYN mentioned that some of her clients do this.)
Like I said in my earlier post, educating ourselves is the key. We don't want to take just anybody's word for something this important to us.