Oocyte activation: A solution for low fertilization rates in ICSI

Intracytoplasmic Sperm Injection (ICSI) is a highly successful IVF technique where a single sperm is injected directly into an egg. While ICSI bypasses many natural barriers, failed fertilization can still occur. In approximately 1% to 3% of ICSI cycles, none or very few of the injected eggs fertilize.

When fertilization fails despite the sperm being placed inside the egg, the issue is often a failure of egg activation. Fortunately, an advanced laboratory technique known as assisted oocyte activation AOA can resolve this issue, restoring fertilization success rates.

What Is Oocyte Activation?

In natural conception, fertilization requires the egg to be "activated" to begin cell division. This activation is triggered by calcium oscillations inside the egg, driven by a protein (PLC-zeta) in the sperm head. If the sperm lacks this protein or the egg fails to respond, activation fails, and fertilization stops.

How AOA Works

AOA is performed immediately after standard ICSI:

1. Sperm Injection: The sperm is injected into the egg.
2. Calcium Bath: Eggs are placed in a medium containing a **calcium ionophore** for 10 to 15 minutes.
3. Cellular Trigger: The ionophore allows calcium to flow into the egg, artificially triggering the cell division signals.
4. Normal Growth: Eggs are washed and placed in an incubator. Learn about embryo development in our blastocyst formation guide.

Advanced Embryology Solutions
Utilizing advanced laboratory activation is key to overcoming past fertilization failures. If you have experienced failed fertilization cycles, you can schedule a clinical consultation with our embryology team at Pravi Global IVF.

Success and Safety

In patients with past activation failures, AOA restores fertilization rates to **60% to 70%**. Follow-up studies show no increase in birth defects or developmental delays in children born via AOA compared to standard ICSI.

Conclusion

Unexplained fertilization failure in ICSI can be frustrating, but understanding how assisted oocyte activation AOA works highlights the power of modern embryology. By using calcium ionophores to trigger the cellular signals needed for division, AOA bypasses activation barriers.

Our embryology team offers advanced micromanipulation and assisted activation. Contact Pravi Global IVF today to schedule your consultation.