News Health & Medicine Hormone wards off immune cells in womb By Ben Harder October 17, 2001 at 2:43 pm - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print A hormone known for its involvement in the brain’s response to stress also plays a key role in shielding the developing embryo from its mother’s immune system. In its newly identified function, corticotropin-releasing hormone (CRH) stimulates the production of a protein previously found to prevent maternal immune cells from attacking embryonic tissue.