Freezing the Biological Clock

The proverbial “biological clock” is not just a myth. 

A woman’s fertility begins to decline around age 27.   In fact, even in her late 20’s and early 30’s, more than half of a woman’s eggs are chromosomally abnormal.  Egg quality declines with age so that in the early 40’s, the percentage of “competent” eggs decreases to less than 5% on average.  This is an irrevocable fact.

Though we can’t change the rate at which a woman’s reproductive system ages, we are now much closer to stopping the biological clock via another route: egg freezing and banking. 

There are numerous reasons for a woman to preserve her fertility through egg freezing/banking.  These include fertility-threatening cancer treatment, postponement of child bearing for career purposes, lack of a suitable partner, and various other issues of timing and choice. 

Obstacles to Successful Egg Freezing

Women seeking viable options for fertility preservation have long faced a difficult barrier due to the poor success rates for egg freezing.  Pregnancy rates for women using frozen/thawed eggs have historically been less than 4% for each individual egg frozen.  This is due to several factors:

First, at least 60% of eggs frozen are chromosomally abnormal from the outset and therefore cannot produce a normal embryo.  Second, traditional (slow) egg freezing techniques cause ice crystal formation within the structure of the egg, reducing viability or destroying the egg in the process. 

The Solution

A recent breakthrough by researchers at the Sher Institutes for Reproductive Medicine (SIRM) and its affiliate, ReproCure Genetics, addresses both of these issues, yielding a promising advance in the viability of egg freezing/banking. 

First, using a proprietary process known as CGH (Comparative Genomic Hybridization), each egg is tested for its chromosomal integrity prior to freezing, ensuring that only the “competent” ones are frozen. 

Second, a new method of ultra-rapid freezing (modified by ReproCure) called Vitrification is used, allowing much more successful freezing without ice crystal formation. 

The combination of chromosome analysis through CGH and Vitrification to preserve the eggs has resulted in post-thaw pregnancy rates that are more than 8 times higher per egg stored than previously reported methods. Initial studies at SIRM/ReproCure have already resulted in many births from frozen eggs using this technique.  These exciting breakthroughs promise to finally open the door to viable fertility preservation for women.

Do you have more questions about egg freezing and how it might relate to the way eggs are fertilized and to IVF?  Come over to the INCIID Community Forums where Dr. Saleh (a reproductive endocrinologist) who will answer your questions online daily.