The pharmaceutical companies would rather process products that create nasty side effects, fund studies that support these products. Then they can sell another chemical drug to combat the side effects of the first drug and so on. The other problem is a great deal of misinformation being given to the physicians on the part of the manufacturers of chemical drugs. Physicians take the word of the manufacturers on the safety of these products. There is even confusion over the words Progesterone and Progestin.
Progesterone is the non-toxic form.
Progestin is the synthetic form. However one really needs to read the label to know which is which. Another clue is if you need a prescription for it, it's not natural. Synthetic progestins have undergone molecular alternations at unusual positions. The body knows how to read the molecules of natural progesterone and goes to work metabolizing it properly.