AN ULTRASTRUCTURAL ANALYSIS OF AN OOCYTE FROM AN IN-VITRO FERTILIZATION PATIENT WITH REPEATED POLYSPERMIC FERTILIZATION

Objective: Our goal was to determine any ultrastructural anomalies in an oocyte from a patient with a history of polyspermy. Results: Ultras tructural observations of the cortical ooplasm of several oocytes from each of three control patients showed a large population of intact co rtical granules. Conversely, one oocyte from a patient with repeated p olyspermic fertilization contained a relative paucity of granules in t he cortex. Quantitative analysis of the cortices of control oocytes in dicated that there were 17.02 +/- 0.52 cortical granules present per m easured field of view, compared with 4.40 +/- 2.92 granules per field in the other oocyte. Conclusions: The presence of sufficient cortical granules is necessary for normal (monospermic) fertilization to occur: When contrasted to the cortical granule population of oocytes from se veral control patients, the cortex of one oocyte from the other patien t showed few of these organelles. Therefore, the absence of a sufficie nt number of granules may have precluded normal fertilization from occ urring in the eggs of this patient.