In vitro maturation of oocytes.

In vitro maturation of oocytes is a safe and effective treatment offered in some fertility centers for assisted reproduction, where immature oocytes are retrieved from unstimulated ovaries. Therefore, the procedure avoids ovarian stimulation with expensive gonadotropins, side effects of the medications, and risks such as ovarian hyperstimulation syndrome. Added advantages are reduced frequency of monitoring scans and shorter treatment regimen compared with in vitro fertilization. The candidates initially considered were women with polycystic ovaries having multiple antral follicles, but the indications are widening to include women with primarily poor quality embryos in repeated cycles and poor responders to stimulation. The two new applications for in vitro maturation we are now successfully implementing at McGill Reproductive Center are for oocyte donors and for fertility preservation, especially in women with cancer who are undergoing gonadotoxic therapy. In young women without partners needing this treatment for fertility preservation, it is combined with vitrification of the oocytes. We have achieved a 38% clinical pregnancy rate per cycle in women having IVM for infertility treatment up to the age of 35 years, and 50% clinical pregnancy rate per cycle in recipients of IVM egg donation.