Cryopreservation is already one of the most significant tenets of contemporary IVF. This is because the safety of freezing and storage of eggs, sperm, embryos, and so on has revolutionized fertility treatment, providing flexibility, increased cumulative success rates, and patient results. Nevertheless, freezing is not the same technique.
In laboratory terms, the issue is usually reduced to vitrification vs slow freezing. We are of the opinion that patients should be acquainted with what actually goes on in the IVF lab at Embryologist and why one approach is now better than the other.
This blog is a definitive lab-side comparison of vitrification and slow freezing, as it is described in simple terms, but based on the science of embryology.
What Is Slow Freezing?
The Traditional Method
The conventional method of cryopreservation that had been employed over several years in IVF labs was slow freezing. As the name implies, it is the process of slowly reducing the cell temperature over a number of hours.
How It Works in the Lab
- Cryoprotectants are subjected to low concentrations in cells.
- The temperature is lowered gradually with the aid of programmable freezers.
- Ice crystals are formed slowly both internally and externally in the cell.
- Samples were kept in liquid nitrogen.
What Is Vitrification?
The Modern Gold Standard
Vitrification is an extremely fast freezing method, which has been adopted mostly in the sophisticated IVF laboratories, substituting slow freezing.
How It Works in the Lab
- There is an exposure of cells to increased levels of cryoprotectants for a short period.
- Almost instantly, the temperature is lowered.
- The water within the cell is converted to a glass-like solid (no ice crystals).
- Samples are plunged directly into liquid nitrogen.
In Embryologist, the most favoured mode of embryo and egg freezing is through vitrification because it has a higher success rate.
Key Lab-Side Differences Between Vitrification and Slow Freezing
Ice Crystal Formation
- Slow Freezing: Ice crystals will be created and could destroy cells.
- Vitrification: No crystals of ice are created.
This is the only difference that makes vitrification have superior results, particularly in the delicate cells such as eggs and blastocysts.
Survival Rates After Thawing
- Slow Freezing: Mediocre survival, increased chances of cell damage.
- Vitrification: The survival is usually above 90 to 95 percent.
Lab-wise, the quality of embryos after thawing is significantly enhanced through vitrification.
Time Required
- Slow Freezing: A few hours per batch.
- Vitrification: Finished in minutes.
This will make the embryos less exposed to environmental stress and enhance the lab workflow.
Equipment Dependence
- Slow Freezing: This needs costly programmable freezers.
- Vitrification: This is a procedure that is more of an embryologist than an embryo machine.
This renders vitrification as a method in which training and accuracy are more important than automation.
Skill Level of the Embryologist
- Slow Freezing: Less operator-dependent, more automated.
- Vitrification: Extremely technique-sensitive.
In Embryologist, embryologists receive specialised training since in vitrification, there is no room to make mistakes in timing.
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Why Vitrification Works Better for Eggs and Embryos
Eggs are the largest cells of the human body, which have a high percentage of water. This renders them very susceptible to ice crystal damage.
Vitrification:
- Preserves cell membranes
- Holds the integrity of the spindle.
- Shields the positioning of the chromosomes.
- Enhances the fertilisation following thawing.
That is why now vitrification is regarded as necessary to:
- Egg freezing
- Blastocyst freezing
- Cancer patients and fertility preservation.
Are There Any Risks with Vitrification?
Lab-wise, vitrification is very safe so long as it is done properly. However, it requires:
- Precise timing
- Precise exposure to cryoprotectants.
- Skilled handling
- Strict protocol adherence
Poorly trained laboratories may result in osmotic shock due to improper vitrification. This is the reason why it is important to select a centre that has experienced embryologists, such as the ones at Embryologist.co.in.
Conclusion
Lab-wise, it is apparent that vitrifying eggs and embryos is better than slow freezing. It provides improved survival, preservation of cellular integrity, and an increased success of IVF.
Not only is vitrification a method, but a skill.
Vitrification at Embryologist is done with care, practice, and respect to the delicate life in its lowest stage of development. Freezing is not about time cessation, but freedom of potentiality.