[9] Indian Hedge Hog, (Ihh) is one of three signaling molecules from the Hedgehog (Hh) gene family.

[10] Recently, Ihh mutations are shown to cause brachydactyly type A1 (BDA1), the first Mendelian autosomal dominant disorder in humans to be recorded.

Studies have shown progesterone to upregulate Ihh expression in the murine endometrium, suggesting a role in implantation.

[13] Ihh is suspected to be involved in the downstream regulation of other signaling molecules that are known to play a role in murine implantation.

[14] Mouse models involving Ihh null mice demonstrated failure of attachment and decidualization.