I don't want to disagree but wild yam is considered a phytoestrogen.....it needs a component to help the body change it into a progesterone.

[The wild Mexican yam contains a phytoestrogen that is closely related to human progesterone, but requires a simple molecular manipulation to become identical. That is why yam creams alone are not effective; their phytoestrogens must be transformed into progesterone...]

[Wild Yam, also known as Colic Root, Barbasco, it contains a powerful ˇ°estrogen-likeˇ± phytochemicals. Wild Yam can nourish female reproductive system and benefits the urinary, digestion, nervous and respiratory system. Wild Yam can also ease various painful conditions such as arthritis and rheumatism. ]
http://www.ihealthtree.com/wild-yam.html

You can give wild yam to pregnant women to help with nausea and a pregnant woman cannot take progesterone.