Cryopreserved Oocytes: Update on Clinical Applications and Success Rates

Importance Over the past 3 decades, oocyte cryopreservation procedures have improved rapidly. However, there is limited research reviewing the efficacy of different cooling protocols and inadequate data comparing in vitro fertilization (IVF) outcomes from fresh oocytes with cryopreserved oocytes. Objective The present review was performed to investigate advances in oocyte cryopreservation technologies and identify areas for further research, to determine whether results from IVF using cryopreserved oocytes are comparable to IVF using fresh oocytes, and to identify the patient populations requiring access to oocyte cryopreservation. Evidence Acquisition A literature review was conducted. OVID (MEDLINE) and PubMed databases were queried using phrases such as oocyte or egg and cryopreservation, vitrification, or slow cooling or slow freezing. A total of 180 studies were selected for review. Results Current literature suggests that vitrified oocytes produce superior IVF results to slow-frozen oocytes and may yield comparable outcomes to IVF with fresh oocytes in certain patient populations. Patients at risk of infertility due to disease or age-related decline or oocyte donation programs, couples who fail to produce semen when required for IVF, and patients with legal or ethical reasons against embryo cryopreservation may access cryopreserved oocytes. Conclusions We suggest that women who comprise the previously mentioned patient populations should be offered oocyte vitrification technology. Further research is required to confirm IVF success across all patient populations and determine the best cryopreservation protocols. Relevance This review will be relevant to clinicians interested in fertility treatments using cryopreserved oocytes, fertility preservation, oncology and fertility, and immunology and fertility. Target Audience Obstetricians and gynaecologists, oncologists, immunologists, and rheumatologists Learning Objectives After completing this activity, physicians should be better able to discuss oocyte cryopreservation processes, select patients who may require access to oocyte cryopreservation technology, compare IVF using cryopreserved oocytes with IVF using fresh oocytes, counsel patients regarding the feasibility of oocyte cryopreservation and their chances of pregnancy with cryopreserved oocytes, and implement oocyte cryopreservation as a fertility preservation option in clinical practice.