Human oocyte cryopreservation: evidence for practice.

AIM: The aim of this article is to review the evidence regarding human oocyte cryopreservation by slow freezing and vitrification and to provide evidence-based clinical and laboratory guidelines on the effectiveness and safety of these technologies. SCOPE: These guidelines will address the following: Stage of oocyte maturity. Methods of cryopreservation/warming. Slow controlled cooling. Vitrification. Techniques used for insemination. Ovarian stimulation regimens. The guidelines do not cover recommendations for ovarian tissue freezing or in vitro oocyte maturation (IVM). OUTCOME MEASURES: The following outcome measures were examined: cryosurvival, fertilisation rate, cleavage rate, clinical pregnancy rate and implantation rate, health of resulting children.