IVF Laboratory Procedures Assisted Hatching
There is a protective membrane around the egg and the embryo formed after the fertilization stage. This membrane is called the zona pellucida.
This membrane has many important functions. The most important are:
- It plays a role in the fertilization of the egg and in the nutrition and development of the embryo.
- It prevents polyspermia; in other words, after the egg is fertilized with a sperm, this membrane prevents other sperms from entering the egg.
- It protects the embryo and ensures its integrity.
The membrane around the transferred embryos spontaneously cracks or perforates when it reaches the blastocyst stage. This is called hatching. After the perforation of the membrane, the blastocyst comes out of the membrane and comes into direct contact with the endometrium tissue and the adhesion process takes place. In some cases, it is thought that this event becomes difficult or cannot be realized.
In IVF applications, the process of thinning or completely puncturing the outer membrane around the embryo before embryo transfer is called “Assisted Hatching”. A hole to be created in the zona pellucida facilitates natural hatching. The purpose of performing this procedure is to increase the chance of attachment (implantation) of the embryo. It is necessary to perform this procedure especially on the outer membranes of frozen and thawed embryos.
Assisted Hatching can be done by various methods (mechanical, using acid thyroid or laser). In our center, Assisted Hatching is done using laser. It is a reliable and useful technique. The application time is very short (5-20 ms).
The laser beam passes through the microscope objective and, at the focus point, it gives its energy to the zona pellucida macromolecules and the fluid in the zona pellucida. Thermal effect develops. Melting occurs in the zona pellucida due to the increased temperature. The drilled hole is well-defined and controlled.
To whom Assisted hatching is applied?
- If there is recurrent IVF failure
- If the age of the woman is over 35
- Before frozen embryo transfer
- In the presence of thick zona pellucida (>15 µm)
- Abnormal zona pellucida. Especially in oval-shaped oocytes and embryos, the zona pellucida may be completely or partially double-layered.
- Dark cytoplasm
- In case of extensive cytoplasmic fragmentation, assisted hatching must be performed.
