Egg freezing: Does the reason for freezing affect the outcome?
In the past twenty years egg freezing has been offered as an option to preserve fertility for women who are diagnosed with cancer and are about to undergo chemotherapy that might affect their fertility. This is called ‘onco fertility preservation’ (OFP). Advances in egg freezing techniques in the last ten years have improved the chance of having a baby from frozen eggs. As a result, more and more women around the world now turn to egg freezing for non-medical reasons to guard against age-related fertility decline. This is called elective fertility preservation (EFP).
To answer the question if the reason for egg freezing affects the chance of having a baby from the eggs, researchers in Spain looked at data from all women who had frozen eggs at their clinic between 2007 and 2018. In all, 6362 women had frozen eggs in that period, (5289 for EFP and 1073 for OFP). The women in the EFP group were older than the women in the OFP group (average 37 years versus 32 years) and their eggs had been stored for a shorter time when the study was conducted (about 2 years versus 4 years) but they had a similar number of eggs stored (12 eggs on average).
At the time of the study 641 (12.1%) EFP and 80 (7.4%) OFP women had returned to use their eggs to attempt pregnancy. Of these about one third in each group had given birth or were still pregnant (229 of 641 (36%) EFP and 25 of 80 (31%) OFP women). The researchers concluded that the reason for freezing eggs did not affect the chance of having a pregnancy but older age at the time of egg freezing reduced the chance of success in the EFP group.
Cobo A, García-Velasco J, Domingo J, Pellicer A and Remohí J. Elective and Onco-fertility preservation: factors related to IVF outcomes. Hum Reprod 2018:dey321-dey321.