The day following your egg collection (Day 0) is when we check for fertilisation (Day 1), and you will be contacted with the number fertilised.
This image is what we are looking for:
This is a normally fertilised egg. The two structures in the middle are called pronuclei, and there is one from the female and one from the male. The two structures just outside of the egg, between the egg and the zona pellucida (outer shell) are called polar bodies, and the two signify the chromosomes are dividing correctly.
Any non-fertilised eggs could be a variety of things:
• Immature eggs
• Abnormally fertilised eggs (more than 2 pronuclei)
• Degenerate eggs
We will only keep the normally fertilised eggs, and will culture them until the blastocyst stage (Days 5 and 6), at which point we will assess them for suitability for freezing.