In Vitro Maturation of Mammalian Oocytes: Outcomes and Consequences

The application of in vitro maturation (IVM) of oocytes as a technology to assist animal production and clinical infertility treatment remains poor because of the reduced developmental competence of oocytes after IVM, despite several decades of research. Reduced meiotic maturation rates, fertilization rates, and blastocyst production reveal short-term developmental insufficiency of oocytes when compared with in vivo-matured counterparts. However, there is an increasing body of evidence that demonstrates the capacity of IVM efficiency to be improved, some of which is reviewed here. Of more concern is the role that IVM of oocytes may play in causing or accentuating long-term development and health of fetuses and neonates after in vitro production of embryos and embryo transfer. This is a largely unexplored area, yet the application of such techniques, especially the safety of clinical IVM, is significant and requires monitoring before acceptance as a routine procedure.