The language on Joh Hopkins website is being deliberately conservative. The reality is we have almost no data on eggs that have been frozen longer than 10 years, so they say 10 years becuase we don’t have direct evidence for them being viable longer. What data we do have on eggs that have been frozen and then used after 4-8 years indicates time frozen has no effect on survival rates or fertilization rates. It would be very surprising to me if there’s no impact on survival after 8 years, but at 10 years they suddenly start to degrade.
You can look a little further afield for more direct evidence of the long-term efficacy of freezing for fertility preservation. There are some neat animal studies in which sperm frozen for 50 years was used to create sheep, with the authors noting that the pregnancy rate of the frozen semen was identical to the pregnancy rate for the fresh semen.
My best guess is you’d see essentially zero degradation from longer freezing periods.
The language on Joh Hopkins website is being deliberately conservative. The reality is we have almost no data on eggs that have been frozen longer than 10 years, so they say 10 years becuase we don’t have direct evidence for them being viable longer. What data we do have on eggs that have been frozen and then used after 4-8 years indicates time frozen has no effect on survival rates or fertilization rates. It would be very surprising to me if there’s no impact on survival after 8 years, but at 10 years they suddenly start to degrade.
You can look a little further afield for more direct evidence of the long-term efficacy of freezing for fertility preservation. There are some neat animal studies in which sperm frozen for 50 years was used to create sheep, with the authors noting that the pregnancy rate of the frozen semen was identical to the pregnancy rate for the fresh semen.
My best guess is you’d see essentially zero degradation from longer freezing periods.
Yes, once stored in liquid nitrogen eggs will be fine indefinitely