Friday, December 09, 2016

Treating the fragile egg syndrome

How to do ICSI when the eggs are very fragile

This is a guest post from  Dr Saiprasad, our Chief Embryologist.

When we do ICSI we introduce a single sperm into the egg in order to fertilise it. Puncturing the cell membrane of the egg  cleanly with the sharp hollow ICSI pipette is a key part of the ICSI technique, and requires a skilled embryologist to do this properly. If it's done clumsily, the egg will die.

Most normal eggs have an elastic cell membrane. We need to penetrate this with the sharp ICSI needle in order to introduce the sperm into the cytoplasm of the egg. If we do not break the membrane, the sperm will remain outside the egg , and will not be able to fertilise the egg, resulting in ICSI failure.

On the other hand,  if we apply too much pressure, and suck up too much of the egg's cytoplasm into the ICSI pipette, the egg will die. This is why the resilience of the egg's cell membrane is so important.

What do we mean when we say “The Eggs are Fragile”? When the Eggs have a Soft cell Membrane, they die when we do ICSI. When we introduce the ICSI needle to inject the sperm into the Egg, the egg cannot with stand the sharpness of the needle , and hence it dies after ICSI. The problem is that these eggs look completely normal, and it's only when we actually do the ICSI do we realise that the eggs are fragile.
Another major issue is that the death of the egg may not be instant, and we only realise it had dies when we examine it a few minutes after doing the ICSI, by which time the damage is already done.

Another issue is that because the results of ICSI  are so dependent on the skill of the embryologist,  in most cases the death of an egg after ICSI because of a clumsy embryologist, and not because the eggs were fargile.

Recently we treated a patient who had a history of having Fragile Eggs. She had undergone 3 ICSI cycles in Sweden earlier . In all her cycles, the eggs  had degenerated (died) after performing ICSI, and she had never had good quality embryos to transfer

We have encountered excessive fragility of eggs  in the following groups:
1)    SMALL SIZED FOLLICLES : When the Eggs are retrieved from small sized follicles (Size < 10 mm), they usually turn out to be fragile , even if they are mature Eggs.
2)    AGE : We usually see that patients above 40 years, with low AMH, produce few eggs which are often Fragile.

What can we do to handle such fragile Eggs , in order to reduce their degeneration rate and achieve a better fertilization rate ?

When we suspect the Eggs to be fragile, the best option is to do Conventional IVF, which doesn’t involve manipulation of gametes using needles.  With IVF, the risk of degeneration because of the mechanical insult of the ICSI pipette is zero..
However, we cannot do Conventional IVF for all patients, as good Sperm Quality is
a  Prerequisite for doing IVF. If the Sperm count and motility are poor, we are forced to do ICSI, otherwise we will end up with total fertilisation failure.

It is possible to reduce the Fragility of Eggs by incubating them in vitro before doing ICSI.. Even if the eggs are mature, their cytoplasm may be immature after the egg retrieval.  This is why it is advisable to incubate the Eggs after Egg collection for at least an hour, to avoid damage to the eggs due to cytoplasmic immaturity.
A prolonged long incubation of Eggs usually helps in the case of fragile Eggs. We incubate the eggs for 3-4 hours post egg collection if we suspect the eggs to be fragile .

In ICSI, when we inject the sperm into the Egg, little bit of the egg's cytoplasm is aspirated into the pipette to break the cell membrane ( oolema ). This is needed to activate the Egg, which is very Critical for fertilization.

In the case of fragile eggs, we need to modify our technique.
While injecting the Sperm into the Egg, when we pierce the ICSI needle into the Egg, we usually see an indentation due to the elasticity of the cell membrane and the cytoplasm . We then aspirate a little bit of cytoplasm to break the oolema. However, if if the Egg is fragile, we usually do not see any indentation as the membrane of the cytoplasm is very soft. In fact, this is the first clue we get that the egg may be very fragile !

Normal Egg during ICSI (Indentation in Cytoplasm)                 

Fragile Egg during ICSI (NO Indentation in Cytoplasm)      

If we do not see any indentation when the ICSI pipette is advanced into the egg, it is advisable not to aspirate the cytoplasm, because this can damage the  fragile egg.
However, this is a tricky call, because if we do not aspirate Cytoplasm, we may end up having no fertilization as the cell membrane may not break, and the sperm maybe deposited outside the membrane.

We need to treat Each Egg as an individual  Patient , rather than doing ICSI for all the eggs at one time.
Injecting 1 egg at a time is the best option when we are suspecting Eggs to be Fragile.
This can help to minimize damage to the Eggs, because the embryologist is much more aware, and can modify his technique for each individual egg.

The Embryologist can inject 1 Egg; put it back into the incubator, wait for some time, and then observe after a few minutes if the egg has degenerated or not. This is because it can take time for a dead egg to look dead ( the cytoplasm turns dark), and if the embryologist injects all the eggs in a single batch, he may not even realise he has killed a lot of the eggs until it is too late.

After evaluating the fate of the first Egg, the Embryologist can then decide about whether or not to aspirate the cytoplasm for the other eggs. This way he can modify and adapt his technique, depending upon how the eggs behave.

This needs patience, and self-awareness on the part of the embryologist, but this can make a world of a difference to the patient !

No comments:

Post a Comment

Get A Free IVF Second Opinion

Dr Malpani would be happy to provide a second opinion on your problem.

Consult Now!