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Assisted Oocyte Activation
Assisted oocyte activation is a laboratory step performed after ICSI that supports the initiation of fertilisation when the natural signal between the sperm and the oocyte is insufficient.
The procedure is performed on mature oocytes in the embryology laboratory and does not require any additional intervention, anaesthesia or recovery for the patient.
At Adella Clinic, we discuss this option after a careful review of previous treatment, when fertilisation has not occurred following ICSI or when only a very small number of oocytes have fertilised.
The procedure is performed on mature oocytes in the embryology laboratory and does not require any additional intervention, anaesthesia or recovery for the patient.
At Adella Clinic, we discuss this option after a careful review of previous treatment, when fertilisation has not occurred following ICSI or when only a very small number of oocytes have fertilised.
Duration
Assisted oocyte activation is performed in the laboratory shortly after the sperm has been injected into the oocyte using ICSI.
Stay at the Clinic
The procedure does not require any additional stay at the clinic beyond the other stages of IVF treatment.
Feeling
No additional medication, anaesthesia or recovery is required for the patient.
Additional Signal to Initiate Fertilisation
When does fertilisation need support?
How does the natural process occur?
- During ICSI, the embryologist injects a selected sperm cell directly into a mature oocyte.
- Biological processes must then take place between the two cells to initiate fertilisation.
- One of the most important of these is the calcium signal that activates the oocyte.
What can interfere with this process?
- The enzyme PLCζ, which is contained in the sperm cell, plays a key role in generating the calcium signal.
- Sometimes, the signal is insufficient due to factors related to the sperm, the oocyte or the interaction between them.
- In such cases, ICSI may have been performed correctly, but fertilisation may not proceed.
Individual Assessment Following Analysis of Previous Cycles
When might we discuss the procedure?
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1
Following complete fertilisation failure
A key indication is a previous ICSI cycle in which none of the mature injected oocytes fertilised normally.
Rather than automatically repeating the same approach, we analyse what happened and assess whether activation could help address the specific problem. -
2
When the fertilisation rate is very low
The procedure may be discussed when fewer than 30% of the mature oocytes fertilised following ICSI.
This percentage is a guide. The decision also depends on the number of oocytes and the overall embryological picture. -
3
In cases of globozoospermia
Globozoospermia is a rare condition in which the sperm cells have round heads and an absent or severely impaired acrosome.
The condition is often associated with insufficient PLCζ and the absence of the signal required to activate the oocyte. -
4
When there is evidence of impaired activation
Sometimes, the results of a previous cycle indicate a problem with activation even when globozoospermia has not been identified.
In these cases, we consider factors related to the oocyte, the sperm and the interaction between them together
