After IVM, COCs were washed once in fertilization medium and placed in 50-mL drops of fertilization medium in groups of 20 to 30 under mineral oil. Fertilization medium consisted of modified Tyrode lactate medium (fert-TALP) [9], supplemented with enicillamine (21.1mM), hypotaurine (10mM), epi-nephrine (1mM), and heparin (10mg/mL).