Oncofertility: Cryopreservation and Alternative Options

Ovarian stimulation followed by oocyte aspiration has facilitated a number of cryopreservation techniques. Embryo cryopreservation has become a well-established and highly endorsed form of fertility preservation in young female cancer patients (American Society for Reproductive Medicine, American Society of Clinical Oncology, European Society of Human Reproduction and Embryology, British Fertility Society)1–3. The first pregnancy after a frozen and thawed embryo cycle was reported in 1983, followed by the first live birth 1 year later4,5. Success rates have been improving continuously since. Canadian Assisted Reproductive Technologies Register data from 2007, involving more than 2700 frozen embryo transfer cycles in women less than 40 years of age, showed clinical pregnancy rates and live birth rates of 24.7% and 18.6% respectively per cycle started. Overall embryo survival rates after thawing have ranged from 35% to 90%, and implantation rates, 8% to 30% per embryo transferred6. However, many of the quoted success rates have not yet taken into account the improved survival and outcomes ABSTRACT