Human oocyte cryopreservation: a valid alternative to embryo cryopreservation?

Area of Science:

• Reproductive Medicine
• Cryobiology
• In Vitro Fertilization (IVF)

Background:

• Human in vitro fertilization (IVF) has evolved, necessitating embryo cryopreservation due to ethical considerations and the drive to maximize oocyte yield.
• Current IVF practices, including the collection of multiple oocytes and subsequent embryo creation, lead to surplus embryos, raising ethical dilemmas and practical challenges like co-ownership disputes.
• The trend towards single embryo transfers and improving embryonic viability makes the production of excessive surplus embryos increasingly inappropriate.

Purpose of the Study:

• To explore oocyte cryopreservation as a viable alternative to embryo cryopreservation in IVF therapy.
• To address the ethical concerns and practical complications associated with current embryo cryopreservation methods.
• To evaluate the potential of oocyte cryopreservation in optimizing donor oocyte banking and preserving reproductive potential.

Main Methods:

• Review of current practices in human in vitro fertilization (IVF) and embryo cryopreservation.
• Analysis of the ethical and legal challenges posed by cryopreserved embryos.
• Discussion of advancements in oocyte cryopreservation technologies, including vitrification and in vitro maturation.

Main Results:

• Oocyte cryopreservation offers a potential solution to ethical concerns regarding embryo freezing and legal issues arising from separated couples.
• Vitrification technology and standardization of protocols are advancing routine single oocyte cryostorage at all maturity stages.
• Oocyte cryopreservation can optimize donor oocyte banking, reduce costs, and improve convenience compared to frozen embryo donation.

Conclusions:

• Oocyte cryopreservation, coupled with in vitro maturation, is moving towards routine clinical application, potentially reducing the need for excess embryo production.
• This shift will enable IVF programs to consider cryostoring excess oocytes instead of embryos, inseminating a limited number post-thaw.
• The widespread clinical application of human oocyte cryostorage is anticipated in the near future, transforming IVF practices.