Cryopreservation of Ovarian Tissue: Reimplantation Rate and Effects on Ovarian Function

Premature ovarian failure (POI) is a clinical syndrome defined by the loss of ovarian activity before age 40. POI is characterized by amenorrhea or oligomenorrhea with elevated gonadotropins, low estradiol and serious consequences on fertility. The prevalence of POI in the general population is about 1%. In recent years, the incidence of iatrogenic POI in cancer women is increasing: 4% of patients of fertile age are diagnosed with neoplasms and gonadal treatments that can sterilize them, such as chemotherapy and radiotherapy. Preserving fertility is a key objective for many cancer patients. Before gonadotoxic treatments, patients in the post-pubertal age with future desire for pregnancy may opt for two main methods of preservation of fertility (FP): egg cryopreservation (OC) after ovarian stimulation and cryopreservation of ovarian tissue (OTC). An important limitation of the latter technique is the reduced number of patients who return to use the cryopreserved material, leading to a negative impact on the evaluation of the effectiveness of the procedure. The best way to maximise the effectiveness of the procedure in clinical and economic terms would be to increase the number of patients who continue the cryopreservation path by completing it with subsequent reimplantation. It would also be useful to improve the follow-up of these patients by evaluating their ovarian function over time, before and after the removal and reimplantation, through the study of bone metabolism, cardiovascular risk and psychological function in these women.