Freezing Eggs: Immature vs. Mature - What You Need to Know

Question
Do immature eggs withstand freezing better than mature eggs?  Thank you.  (Question from the Northwest).

Answer
Hello Linda from the U.S.,

I am not sure that you have the terminology correct so if this answer does not suffice, please send a followup question.  

Although you can freeze immature eggs, then allow them to mature in culture, that technology is not main stream and only being used in experimental situations.  It is called in vitro maturation.  The main stream currently is to freeze mature eggs only.  These are called M2 or Meiosis stage II eggs.  The reason only mature eggs are frozen is because only mature eggs will fertilize or can be fertilized at this time.  Hopefully in the future, once the IVM technology gets better and therefore becomes main stream, we can take any eggs, including immature ones and mature them in the lab to use.

Good Luck,

Dr. Edward J. Ramirez, M.D., FACOG
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program
www.montereybayivf.com

Monterey, California, U.S.A.

for additional information check out my blog at http://womenshealthandfertility.blogspot.com check me out on twitter with me at @montereybayivf and facebook @montereybayivf