Lack of the oocyte extracellular matrix region (zona pellucida). This feature can be observed following follicular aspiration (retrieval of eggs for fertility treatments).
Comment:
During in vitro fertilization treatment, oocyte retrieval is performed after ovarian stimulation via vaginal puncture. Cumulus-oocyte complexes, which consist of cumulus cells surrounding the centrally located oocyte, are isolated from the individual's follicular fluid. This term refers to the finding of oocytes lacking zonae pellucidae.