Deb (dmd),
Regarding your question, here is how I decided in bio identicals.
My journey started when I was 45,I started having perimenopause symptoms, long story short, my gyno put my on low dose birth control pills which alleviated all my symptoms, pretty much! I didn't know anything about perimenopause so I read and read and read on the subject. Bio identicals were just coming out and I read that even though this type of hormone was synthesized in a lab, it comes closest to what our body makes naturally. I couldn't start on the HRT right away because I was still having periods, sporadically mind you, and didn't qualify as menopausal. Meaning, if I took HRT while my body was still producing a higher level of estrogen I would be getting too much. The birth control pill actually works by taking total control of your cylce, shutting off the body's production of estrogen and progesteron and replacing it with the synthetic form.
So, last year when I pretty much stopped having a period, I transitioned from the low dose birth control pill to Estradiol (estrogen) and Prometrium (progesterone). This was not an easy transition by any means because my body had to adjust to the lower strength of estrogen. So, from April of this year until last month, my gyno and I struggled to get me to the right dosage. This usally qualifies as the least amount of estrogen required to alleviate menopausal symptoms. This is different for every woman. My dosage is 1.5 MG Estrodial and 100 MG Prometrium per day. Plus, a bit of vaginal estrogen cream evening so I won't get yeast infections. Evidentely, for some women, Estradiol doesn't reach the vaginal tissue so it can't alleviate vaginal dryness that some experience. We found by adding the cream, this symptom went away.
Sorry so long but I could write a book on the subject
P.S. Interesting to note that even though low dose, according to my doctor the synthetic estrogen in it is actually 100 times stronger than what's in Estradiol.
http://www.lionrx.com/hormone.html Additional reading!