A confocal microscopy analysis of the spindle and chromosome configurations of human oocytes cryopreserved at the germinal vesicle and metaphase II stage.

Background: Routine oocyte cryopreservation remains an elusive technique in the wide range of assisted reproductive technologies available. This study examines the effect of a cryopreservation protocol on the spindle and chromosome configurations of human oocytes cryopreserved at the germinal vesicle (GV) and metaphase II (MII) stage.

Methods: GV oocytes were randomly assigned to one of three groups: (i) control oocytes matured in vitro to MII stage (n = 156); (ii) oocytes cryopreserved at the GV stage and then matured in vitro (n = 90); (iii) oocytes cryopreserved at the MII stage (n = 147).