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In Vitro Maturation: A New Approach to Egg Freezing?
April 15, 2013
Egg freezing provides women an option for future family building. Typically mature eggs are frozen, but what happens to the eggs that are retrieved before they have reached their prime? Scientists are saying that in vitro maturation (IVM) could be employed prior freezing or upon thaw of frozen eggs to coax them into maturity, rather than discarding immature eggs retrieved in an IVF cycle.
A study published in the April issue of Fertility and Sterility sought to discover benefits of retrieving immature eggs, then maturing them in a lab via IVM. Seventy one patients who underwent an antagonist IVF protocol donated a total of 69 immature eggs between February and April 2009. To determine how to maximize the potential for IVM, one group used IVM before freezing eggs, and the other group used IVM after eggs were frozen and thawed. The survival rate and maturation of eggs from each group was evaluated to determine how IVM can best be used in an egg freezing protocol.
Some of the benefits of IVM include:
- The maximum number of eggs and reproductive tissue can be preserved and put to use
- Cancer patients can complete an IVF cycle in less time and with fewer or no stimulation drugs
Some of the risks of IVM include:
- Decreased survival rate of eggs with IVM
- Greater risk of degradation or fragmentation of eggs
Results supported a higher survival and maturation rate with eggs retrieved, matured, and then frozen compared to those frozen while immature. This suggests that fresh IVM protocols are more beneficial than freeze-thaw IVM cycles, and is likely due to exposure to mechanical, thermal, and chemical disturbances during development. These factors have shown to increase risk of aneuploidy, and compromise cell viability. Eggs retrieved later in the development cycle had a greater amount of time for cell growth and healthy development. This data allows researchers to understand that IVM can be a beneficial egg freezing protocol for some patients, if eggs are matured before cryopreservation.