Oocyte cryopreservation: time to come in out of the cold…

Abstract

Sperm cryopreservation as a means of preserving the fertility potential of men has existed for over 50 years, but oocytes (eggs) are such large, delicate structures (imagine a fluid-filled bubble the size of a pin point) that until recently there was little we could offer young women facing a choice between the chemotherapy that could save their lives and the certainty of premature menopause and sterility. The first ‘frozen egg’ baby was born in 1986, but the success rate (100 eggs to produce one baby) was so low that ‘egg freezing’ was neglected for years. Two exciting technological developments (ICSI and dehydro-cryoprotectant) have transformed this picture and now young women who have frozen their eggs can be offered the same chance of a live birth per embryo transfer as women undergoing conventional IVF treatment. Young female oncology patients should now be routinely offered the chance to freeze their eggs before embarking on chemotherapy or radiotherapy. Modern treatment protocols mean that a delay of only 2–3 weeks is required before cancer therapy can be started and even patients with ‘hormone sensitive’ tumours such as breast cancer are not necessarily excluded. Other groups of patients may also want to consider ‘egg freezing’ as a ‘fertility extending’ option such as couples with ethical objections to embryo freezing, women who are not in a position to undertake motherhood yet, women considering becoming egg donors or mothers of baby girls diagnosed with Turner's Syndrome.