Progestins are not cardio-protective like progesterone, creates endothelial dysfunction, risks of arterial disease, clots, leading to strokes, heart attacks and thrombosis; as stated with OBC package inserts. This has been known for 50 years.
Most female HRT uses progestins. Some docs are bio-identical aware.
All women have progesterone levels that drop with age just like DHEA. Leads to PMS, long painful bloody periods, estrogen dominance, over stimulation of breast tissue and endrometrium [leads to fibroids] which can progress to cancers. Progesterone can prevent most of that. There are cases where docs want to perform hysterectomies when progesterone can resolve the problems [they do not know]. Some docs prescribe high progestin OBC for cases for an enlarged uterus, increasing a probability of a cardio vascular event.
As a women's progesterone levels drop, she becomes estrogen dominant -dangerous.
I think that a lot of CV disease in women can be avoided by progesterone replacement and that many of the breast and uterine cancers are avoidable. Everyone also asks why breast cancer increased in the last 50 years. OBC is probably part of the puzzle.
I worked with a women who was faced with surgery. With progesterone, she was able to normalize the size of her uterus and expelled the fibroid bodies, as confirmed with ultrasonic imaging. She was a really fast learner who soon did not need any more help from me after I got her started. [She found me here. I have written about this here before.]
Another women was also able to normalize her uterus which was at a 10 week pregnancy size. Docs made her sick with high progestin OBC, I switched her to OTC progesterone, which resolved that and other problems.
Progestins have high oral availability. Progesterone does not. You can't make OBC pills with progesterone. And transdermal is not reliable enough for birth control. The only HRT solutions are transdermal creams and vaginal suppositories.
I think that a women could do well by applying 2% OTC progesterone with her OBC or progestin based HRT [which is very cheap]. But she would have to understand why, and that is a significant barrier.
OBC has estrogen first pass liver effects, increasing SHBG and lowering FT. Sort of fits the loss of libido that some women experience. OBC is HPOA repressive, reducing progesterone created in the ovaries, increasing the effects of the progestin. With post menopausal HRT, there isn't any progesterone to replace, increasing the cardiovascular risks of the then unopposed HRT estrogens.
HRT based in hormones extracted from PREgnant MARes piss [premarin] contains xeno estrogens.
Many GP's dropped female HRT practice when the premarin and progestin products were seen to be increasing heart attacks [woman's health initiative]. Many women dropped HRT from that news or by doc's directive.