>there are signals being sent to the mothers brain that are suppressing her immune system and allowing her body to accept the foreign body.

Just wanted to add that many miscarriages happen from this process not fully suppressing the immune system and the foreign "thing" in the body being booted out. For some women this happens repeatedly and they need to take medication so that their body doesn't reject, what is basically a parasite, from implanting in the uterus.