The "immunological inertia" of viviparity.
D000818:Animals; D000917:Antibody Formation; D004285:Dogs; D005260:Female; D005333:Fetus / Q000276:immunology*; D006084:Graft Rejection; D006648:Histocompatibility; D007108:Immune Tolerance; D007165:Immunosuppression Therapy; D011247:Pregnancy; D051381:Rats; D012756:Sheep; D016038:Skin Transplantation; D014181:Transplantation Immunology