Rescue in vitro maturation (IVM) of immature oocytes in stimulated cycles in women with low functional ovarian reserve (LFOR)

Rescue in vitro maturation (IVM) is currently not a routine procedure in association with in vitro fertilization (IVF). We compared in a prospectively cohort study of 10 patients with normal functional ovarian reserve (NFOR) and of 25 with low functional ovarian reserve (LFOR), defined by abnormally high FSH and/or abnormally low AMH levels), IVM dynamics of immature oocytes. Following controlled ovarian hyperstimulation in IVF cycles, only immature oocytes underwent rescue IVM (for up to 48 h). Oocyte maturation dynamics, fertilization rates, embryo development, and pregnancy rates were then compared between NFOR and LFOR patients. Though proportion of MI and GV oocytes reaching MII stages within 48 h and rate of maturation of MI oocytes did not differ, in women with LFOR significantly more GV oocytes reached MII stage within 24 h (30.4 vs. 66.9 %; P = 0.013), while fertilization rates and embryo generation numbers were similar between both groups. Rescue IVM, thus, produced 1.5 additional embryos for transfer in women with LFOR and 1.6 in patients with NFOR, a highly significant difference in relative improvement in available embryo numbers for LFOR (+60.0 %) and NFOR women (+16.5 %). Rescue IVM, thus, not only demonstrates different time dynamics between women with LFOR and NFOR but also disproportionate efficacy in improving available embryo numbers for transfer in favor of LFOR patients. 1/7 patients, who reached embryo transfer with only embryos produced via rescue IVF conceived and delivered, proving that rescue IVF in women with LFOR also improves pregnancy and delivery chances. Because of the small number of embryos LFOR patients produce, every additional embryo is of considerable potential clinical significance for them, suggesting that rescue IVM in women with LFOR should become routine practice.