Donor Egg retrieval, fertilization, and day 5 embryo statistics - What's the optimal number?

Hi everyone,

I'm looking at doing a cycle with a proven donor. However, some of her cycle numbers are all over the place--like one cycle she got 21 eggs and 18 embryos but another cycle had just 10 eggs and 6 embryos. I would note that the cycles were each done at different clinics.

Since I'm new to some of this, can you all tell me what would be considered the low end, mid-range, and high end for expectations when it comes to the following:

# of Eggs Retrieved?

Fertilization Rate?

# of Blastocysts by Day 5?

At what number of embryos should a recipient be disappointed (if it's a dedicated cycle)?

Since we all put a fair amount of investment in cycles, I'm trying to understand at what level the numbers fall below the norm.

Thanks!