Improving the maturation rate of human oocytes collected ex vivo during the cryopreservation of ovarian tissue

Purpose The aim of the present study was to improve the in vitro maturation (IVM) procedure using oocytes from surplus ovarian tissue after fertility preservation. Methods Twenty-five patients aged 17–37 years were included in the study. Maturation was compared between oocytes collected in HEPES-buffered medium or saline, and we determined whether transport on ice prior to oocyte collection affected maturation. Two different IVM media were used that were supplemented with and without recombinant human midkine. Mature oocytes were assessed for aneuploidy using next-generation sequencing (NGS). Results On average, 36 immature oocytes were collected from each patient (range 7–90, N = 895). Oocytes recovered from HEPES-buffered medium matured at a higher rate than oocytes recovered from saline (36% vs 26%, p