Freezing or vitrification of egg cells does not normally hurt. The stimulation may cause a bloated feeling, but no pain. The puncture of the ovaries does not hurt, since sedation is applied. On the day of the puncture, on some occasions you may experience some mild discomfort which will go away taking a painkiller, but this is not at all frequent.
There is no real limit. The status of the ovarian reserve however, is what determines the limit. Of course, the ideal is doing this as young as possible. Results are obviously worse from the age of 40 onwards, because the response to the stimulation is reduced and the quality of the egg cells will also be inferior. Therefore, the egg cells will survive the defrosting stage less well and the subsequent pregnancy rates will be lower.
They can be conserved all the time that is needed. According to the current Spanish Law on Assisted Reproduction, while there is a clinically adequate age for their use.
There is a 90% chance of survival when defrosting or devitrifying the embryos.
The likelihood is a bit less than with non-frozen embryos. Nowadays there is a 35% success rate per cycle.
Pregnancy as a result of implantation of frozen or vitrified embryos is completely normal. There is no risk associated with freezing or vitrifying embryos. Nor is there a greater risk of any type of malformations.