[Embryochorionic insufficiency: anatomic and physiologic prerequisites, rationale, definitions and pathogenetic mechanisms].

The paper provides a rationale for the new concept--embryochorionic insufficiency as a combined pathological response of extraembryonic structures and an embryo to different maternal exo- and endogenous disorders; it gives rise to early spontaneous abortions and non-developing pregnancies. The main pathogenetic mechanisms of embryochorionic insufficiency are: 1) endometrial structural incompetence; 2) dyschronism in the development of the extraembryonic coelom, amniotic cavity, yolk sac, and early placenta; 3) insufficient cytotrophoblast invasion; 4) discordant hemodynamic relationships; 5) blood rheological disorders; 6) local inflammation (endometritis); 7) oxidative stress; 8) secondary changes in the placental villi; 9) compensatory responses.