Many people mistakenly believe that many plants contain hormones. Only a few animal hormones have been discovered in plants. Estrone, one of six identified types of estrogen, occurs in a few plants, palm-kernel oil, moghat roots and date palm pollen, for example. The amount of hormones in these plants is minimal. Wild yams do not contain progesterone.
Some yams do contain a sapogenin called diosgenin.
Diosgenin is extracted from the Mexican wild yam in the laboratory. The diosgenin is then converted to pregnenalone and then progesterone, utilizing various reagents and enzymes. This all occurs in the laboratory. The human body cannot convert diosgenin to progesterone. This is why I prefer to use the term Quasi-natural to make a distinction between what is found in nature as is and what occurs in the laboratory.