After retrieval, the first number patients often hear is how many eggs were collected. However, that number is only the starting point. The real goal is to retrieve as many mature eggs as possible.
Not every retrieved egg is mature
During retrieval, multiple eggs may be collected from the ovaries, but not all of them are ready to be frozen. Maturity means the egg has reached the right developmental stage.
A mature egg has reached the proper developmental stage and is biologically ready to potentially be fertilized one day.
Marking maturity
Embryologists determine maturity by identifying whether an egg has an extruded polar body. This indicates the egg is at the metaphase II (M2) stage, where these eggs are considered mature.
Eggs that remain in earlier developmental stages are considered immature, including:
Metaphase I (M1)
Germinal vesicle (GV) eggs
Only mature eggs are usually frozen. Once mature eggs are identified, clinics typically freeze only those mature eggs because those can potentially be used later for family building.
Jullin Fjeldstad, VP of Clinical Embryology & Scientific Operations at Future Fertility, holds a BSc in Biology from the University of Victoria and an MSc in Clinical Embryology from the University of Leeds, UK. With over a decade of experience in the lab, she began her career in 2007 at the Victoria Fertility Centre, quickly progressing to senior embryologist and laboratory director. She now focuses on the clinical implementation of Future Fertility's innovative AI-based tools, scientific collaborations, and sharing research at international fertility conferences.
Learn about Future Fertility’s egg freezing practice on Freeze.
