Laboratory and Embryological Aspects in IVM Cycles

Weon-Young Son *,


Despite a growing collection of translation research and the development of new clinical protocols laboratory and clinical outcomes in IVM remain suboptimal when compared to the standard IVF. One of the most popular approaches in improving IVM success is to supplement follicular development with gonadotropin stimulation (FSH and/or hCG) prior to oocyte collection. In this presentation recent advances in the laboratory and embryological aspects of IVM cycles are described including oocyte identification and characterization in vitro maturation insemination timing of embryo transfer and cryopreservation. In IVM cycles primed with hCG oocyte identification is easier than in non- or FSH-primed IVM cycles due to the presence of an expanding cumulus mass around the oocytes. The immature oocytes with dispersed cumulus cells (CC) at collection in hCG-primed IVM cycles have high in vitro maturation and embryo developmental potential. Moreover a few in vivo matured oocytes with dispersed CC can be obtained and these have produced good quality embryos. Extending the period of hCG priming time before oocyte retrieval was one of the methods utilized to promote oocyte maturation in vivo and in vitro. The hCG could be given to patients when a dominant follicle (DF) reaches 10-12 mm to avoid detrimental effects on the sibling immature oocytes. ICSI has been suggested as the procedure of choice for inseminating mature oocytes and should be performed at least 1 h after the 1st polar body extrusion. Embryo transfer time depends on the quantity and the quality of the embryos produced after IVM. Vitrification is a more efficient method to freeze the embryos produced from IVM rather than slow freezing. In order to improve the IVM programs it is essential to define not only the clinical aspects but also the laboratory and embryological aspects.