Fertility preservation means storing reproductive cells now to use later. For women this usually means egg freezing. You have the same hormone injections and egg collection as in IVF. The mature eggs are then frozen unfertilized by vitrification (very fast freezing) and stored. Embryo freezing (for couples) and sperm freezing work on the same principle.
Who considers it
Two groups usually consider it. The first is people facing medical treatment that can damage fertility, such as chemotherapy, radiation, or ovarian surgery. For them, preservation should be discussed before treatment starts. The second is people who know pregnancy is some years away and want to store eggs while egg numbers and quality are better. The way I frame it for my patients: egg freezing isn't about delaying motherhood — it's about protecting your options.
What it can't promise
Frozen eggs give you a chance later, not a certainty. Success depends on the number and quality of eggs stored, and both are strongly tied to your age when you freeze. The earlier you discuss it, the more options you have.