The Role of In Vitro Maturation in Fertility Preservation

In vitro maturation (IVM) is an advanced embryology laboratory technique whereby immature oocytes, which are removed from ovarian follicles prior to completing their growth in vivo, are cultured from the germinal vesicle (GV) to the metaphase II (MII) stage. Upon reaching maturity in vitro, these eggs can then be fertilized and the resulting embryos can be cultured using conventional in vitro fertilization (IVF) techniques and transferred or cryopreserved. Except in the most experienced hands, IVM is a labor-intensive, experimental technology requiring meticulous laboratory skills in order to maximize embryonic potential. For that reason, its current place among other assisted reproductive technologies is controversial. Nevertheless, IVM has several unique characteristics that make it an attractive option for fertility preservation. Most notably, IVM allows for extreme fl exibility in treatment timing and does not require hormonal stimulation prior to oocyte retrieval from the ovary. This facilitates rapid fertility preservation interventions in the face of impending cancer treatment. It also allows women with estrogen-sensitive cancers to avoid supraphysiologic elevations in serum estradiol levels with ovarian stimulation (Table 6.1 ).