I found the reference: Book - The estrogen alternative by Raquel Market. She states that " Myelin formation is encouraged by progesterone that is manufactured by Schwann cells in the peripheral nerves from the hormone pregnenolone." " A decline of progesterone production in these cells will impair myelin sheath protection of the nerves".

And on anoher note, sometimes, by taking DHEA and or pregnenolone, you can ease menopause symptoms because pregnenolone is a precurser to all the sex hormones. Hopefully your bio-identical hormone doc will look at those levels as well. The benefit to increaseing DHEA to more youthful levels, as well as pregnenolone, is that your body then decides how much and which sex hormones to make. So you may want to read up on these also.

Good point on the thyroid....my sister was alway borderline with thyroid and once her periods stopped, she was experiencing extreme hot flashes. That's when she discovered her thyroid was underfunctioning and they started her on ?synthroid?. She then went on low dose estrogen and found that she needed to modify her thyroid med. So there is definate link to all these hormones. She also dropped all wheat from her diet and says she feels much better in general.