[Failures at in vitro fertilization: electron microscopic studies of unfertilized oocytes and undivided ova].
We have examined by electron microscopy the non fertilized oocytes and the non divided eggs after assay of in vitro fertilization. We have observed three blocking points; 1) absence of fusion of the gametes, either because of oocyte immaturity or over-maturity, either because of spermatozoa phagocytosis by follicle cells transformed in phagocytic cells, in presence of intra or extra-cellular bacteria; 2) fusion of the gametes but absence of spermatic nucleus decondensation; 3) fusion of the gametes and pronuclei formation but absence of amphimixy. Two causes are evident: failure of oocyte maturation in vivo or in vitro, and bacterial contamination problems after female or male infra-clinical infections.
D002970:Cleavage Stage, Ovum; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D009865:Oocytes / Q000648:ultrastructure; D006080:Ovarian Follicle / Q000382:microbiology; D010063:Ovum / Q000648:ultrastructure*; D010587:Phagocytosis; D013084:Sperm-Ovum Interactions
Les échecs de la fécondation in vitro: étude au microscope électronique des ovocytes non fécondés et des oeufs non divisés.