IVM rescue from stimulated cycle: Improvement of oocyte morphology and competency

Oocyte in vitro maturation (IVM) is a technique where immature cumulus oocytes complexes (COCs) collected from mid cycle of follicular phase were maturated via Bi-Phasique maturation named CAPA-IVMor germinal vesicles (GV) and/or metaphase I oocytes (MI) from stimulated cycle are matured in vitro(IVM Rescue). The objective of our study was to evaluate the effectiveness of a new formulation of culture medium, developed by ourselves, in terms of improving oocyte maturation, competency, embryo development potential and quality.

This prospective study involved a total of 60 patients who underwent an ICSI cycle. Six hundred and fifty oocytes were collected including 410 oocytes at the metaphase II, 120 oocytes at the metaphase I and 120 oocytes at the germinal vesicle stages. Immature oocytes were divided into two groups: Group M (immature oocytes cultured in commercialIVM medium from Cooper-Origio) and group MS (immature oocytes cultured in the same medium but supplemented with an in-house mixture of cytokines, interleukins and growth factors). Metaphase II oocytes obtained after IVMunderwent an ICSI attempt. Fertilization rates at day 1 and the numbers of 8-blastomere embryos at day 3 were assessed in all cultures after ICSIuntil blastocyst stage.

While comparing IVM outcomes, we noted a significant increase in the oocyte maturation rate, fertilization rate and the percentage of 8-cell embryos on day 3 in the MS group compared to the M group. Moreover, the MS group also showed a significant increase in blastulation when compared to the MS group (P=0.02).

The development of suitable IVM medium contributes to better rescue maturation of immature oocytes obtained in stimulated cycles. Its use may increase the number of good-quality embryos and thus can improve time to pregnancy and the cumulative pregnancy rate.