In vitro maturation of oocytes as a strategy for fertility preservation.

In vitro fertilization and embryo cryopreservation are regarded as the only established method for the preservation of fertility in female cancer patients. However, a possible delay in the treatment of cancer and exposure to supraphysiologic estrogen levels caused by ovarian stimulation raise concerns for patients and physicians. In vitro maturation avoids treatment delay or exposure to increased estradiol levels associated with in vitro fertilization. In vitro maturation combined with embryo or oocyte vitrification provides options that have been unavailable earlier, such as immature oocyte collection in the luteal phase, for some patients and improves the services provided by a fertility preservation program.