A report published by the Practice Committee of the American Society for Reproductive Medicine (ASRM) has declared that the experimental phase of a human egg freezing technique is now over and that the procedure can now enter into standard clinical practice. This new phase likely means that universal donar egg banking is right around the corner.
The freezing technique, which is called vitrification, is the process of preserving eggs (or any cells for that matter) by applying high concentrations of cryoprotectant followed by ulta-rapid cooling to solidify cells into a glass-like substance. And because ice doesn't form on the cell, its integrity is preserved. The procedure is also being used to freeze embryos, ovarian tissue — and even human bodies (a la cryonics).
But back in 2008, when the vitrification technique was relatively new, the ASRM had put out a preliminary report warning of potential risks. But now, after analyzing over 1,000 papers on the subject, the Committee found the proof they were looking for, declaring that the studies had, "demonstrate[d] acceptable success rates in young highly selected populations."
Now that said, the report made it clear that women who have stored their eggs, or what are more technically called oocytes, should probably get to a pregnancy sooner rather than later. According to the report, "success rates with oocyte cryopreservation via either slow-freeze or vitrification appear to decline with maternal age consistent with the clinical experience with fresh oocytes." Some researchers noticed that pregnancies and delivery rates started to decline after the age of 34.
The report also noted that there isn't enough data yet to know how long eggs can be cryopreserved — but that said, clinicians haven't noticed any problems with oocytes stored for as long as 48 months.
Moreover, the studies also showed that implantation and pregnancy rates may be lower when frozen oocytes are used when compared to fresh, previously unfrozen eggs. That said, the rate was not significant enough to cause any concern.
As for the practice itself, preserving eggs offers women a number of advantages. For special, doctor-prescribed cases, eggs can now be stored until such time as a woman has found the right male donor. It will also allow women to time their pregnancies. And given the prospect of lost fertility on account of chemotherapy (or other gonadotoxic therapies), women can now store their eggs for future use — potentially for eventual fertilization and implantation in a surrogate mother.
Now all this said, the report did not go so far as to endorse the practice for elective use. Because it's still early days, women can only have their eggs frozen on recommendation from their physicians. But looking ahead, and assuming more widespread clinic-specific data on the safety and efficacy of oocyte cryopreservation, it's expected that universal donor egg banking will someday become available (what the authors call Level B).
You can read the entire report here.