Egg cryopreservation: who it is for, what to expect, and what the numbers really mean

Egg freezing has moved from experimental to standard since vitrification became the norm around 2012. The technology now works reliably: thaw survival exceeds 90 percent in good labs. The decisions around freezing – when, how many, what to expect – are where careful counseling matters.

What the cycle looks like

An egg freezing cycle is, mechanically, the first half of an IVF cycle. Daily injections for 8 to 14 days, monitoring scans every 2 to 3 days, a precisely-timed trigger, retrieval under sedation. The difference is what happens next: instead of fertilising the eggs and transferring an embryo, the mature eggs are vitrified and stored in liquid nitrogen.

How many cycles you might need

Live-birth probability per frozen egg: about 7 percent at age 30, 4 percent at age 35, 2 to 3 percent at age 38, falling further beyond. To bank a meaningful reserve – enough for a 70 to 80 percent chance of one live birth – women under 35 typically need 15 to 20 mature eggs; in late thirties, 25 to 35. Most cycles yield 8 to 15 mature eggs in good responders, fewer with diminished reserve.

Most patients therefore need two cycles. Some need three. Coming in with that expectation rather than discovering it after one round is part of an honest consultation.

What changes with age, plainly

Egg freezing protects against the quantity loss of aging – it does not protect against the quality loss. Eggs frozen at 35 are still 35-year-old eggs when thawed at 42; they have not aged in the freezer, but they have not improved either. The earlier you freeze, all else equal, the more you preserve.

The practical realities

Self-injecting nightly for two weeks. Bloating, mood swings, feeling full and tender. Time off work for monitoring scans (usually early morning). Recovery of 24 to 48 hours after retrieval. Storage fees year on year. The eggs you bank may or may not be used; some women never come back to them. That is okay too.

Questions worth asking your doctor

• Given my AMH and age, what is the realistic egg yield per cycle, and how many cycles do you expect we will need?
• What is this clinic’s thaw survival rate, and how is that measured?
• What is the likely per-egg live-birth probability when I come back?
• What does this cost in total – cycle fees, medication, storage – over the next 5 years?
• What if I never use them? What are my options?

This essay is educational. Every patient’s situation is different – the right plan is shaped in conversation with a fertility specialist who knows the full picture.