Oocyte cryopreservation entails important potential advantages for human

IVF, offering a less ethically disputable alternative to embryo cryopreservation,

simplifying and making safer oocyte donation, and giving an opportunity for

fertility preservation to women at risk of premature ovarian failure as an effect

of genetic factors or chemo- or radiotherapies. Oocyte cryopreservation could

also meet the expectations of women wishing to preserve their fertility for

social reasons. In the last few years, advances in cryopreservation

methodologies have dramatically improved the efficiency of oocyte

cryopreservation, leading to the birth of over a thousand babies and

challenging the supremacy of embryo cryopreservation as the preferred

form of fertility preservation. This text has been conceived with the aim of offering a comprehensive view of the state of the art of oocyte cryopreservation. It covers fundamental concepts of low temperature storage (controlled rate slow cooling and

vitrification), aspects of oocyte physiology relevant to the process of

cryopreservation, essential biological and clinical evidence, and ethical

implications of oocyte cryopreservation, thereby providing a complete

overview of progress in this strategy in assisted reproduction.