IVF UFOs.

IVF UFOs.
Three days after insemination. The upper left oocyte may have come from an atretic follicle. Its quality is poor based on its granular, light appearance. The center two oocytes appear normal but did not become fertilized. The two embryos on the right are a 4-cell and an 8-cell respectively [Stage 2].

Hansen PJ (2006)