Day 1 - Fertilisation check

Day 1 - Fertilisation check

When do you check?

On the first day, we need to find out how many of your eggs have fertilized. No matter how we fertilised the eggs yesterday, with IVF, ICSI or MACS-ICSI, the procedure for fertilisation check is pretty much the same. It takes place around 18 hours after we inseminate your eggs or inject the sperm.

How do you do it?

We all hope that things have gone well overnight, but we will not know until we look closely at your eggs. We are looking for signs of ‘normal’ fertilisation and it is easy to spot this using the microscopes we have in the laboratory.

If your treatment involves the use of Embryoscope time-lapse technology, then we do things a little different. Visit our section on Embryoscope to see how it works and what we do with it.



What should I expect?

A normally fertilised egg should have two ‘pronuclei’ (the male and female genetic information which you can see as two small circles within the egg) and two ‘polar bodies´(by-products of cell division that need to be released in the process so that the resulting embryo has normal genetic content). If an egg has fertilized normally these are very clear to see.  If an egg is seen to have more or less than two pronuclei then this has fertilised abnormally and is separated from the normally fertilised eggs.

It may sound silly, but it is perfectly normal for some of your eggs to fertilize abnormally, its nothing at all to worry about. On average we would expect approximately 65% of all injected eggs to fertilise normally from IVF or ICSI treatment.  The average may be lower if you are using surgically recovered sperm or if we know your egg quality is variable.

We will call you on the morning of the Fertilisation Check, usually before 10:30 to let you know how things have gone. We probably do not need to say this, but it is important that you keep close to the telephone, as we know you will want to find out as soon as possible how your eggs have fertilised.