Immunology of pregnancy.

Even though the paradox of the fetal allograft is still not completely understood, advances in reproductive immunology have made various immunological mechanisms apparent which seem to play a part in the tolerance of the fetal allograft by a seemingly normal maternal immune system. Pregnancy immunology is, however, not only restricted to the understanding of the transplant analogy of pregnancy, but has also achieved clinical significance through our increased awareness of immunological mechanisms being implicated in various pregnancy disorders. A review is presented outlining our present understanding of both basic immunological mechanisms and the normal process of pregnancy as well as those abnormal mechanisms which may be implicated in pathological states.