Slow freezing or vitrification: which is the best?

As the clock ticks by, the fertility of a woman decreases considerably. Just like every other organ, the ovaries too, age with time. By the time, a woman turns thirty-five, she has lost approximately a thousand eggs, as a result of her menstrual cycle each month. Roughly, around forty, she has only ten percent of her ovum intact. But, these eggs are usually of a poor quality. This might result in failed attempts of reproduction. Moreover, there are high chances of conceiving an unhealthy baby or giving birth to a baby with potential chromosomal abnormalities.

Thus, it might be a good decision for a woman to freeze her eggs while she is at her fertile best. This will ensure the probabilities of giving birth to a healthy baby in future. It also is a good resort for women who considering on having their ovaries removed due to medical reasons.

Generally, two methods of freezing are widely practised:

1. Slow Freezing

2. Vitrification

 

So, which one between the two is better? Here are some points which can help you differentiate between the two.

 

THE PROCEDURE

 

Slow Freezing

• It is a process of gradual freezing.

• Generally, it takes up to three hours.

• Less amounts of cryoprotectants (anti- freeze agent) are used.

• There are higher chances of ice crystal formation. The formation of ice crystal can kill the cell.

• If pregnancy is desired, the eggs are thawed for fertilization. Thawing itself can diminish the chances of pregnancy by adversely affecting the cell.  

Vitrification

• It is a process of flash freezing.

• Generally, it takes up to ten minutes.

• Higher amounts of cryoprotectants (anti- freeze agent) are used.

• There are lesser chances of ice crystal formation.

• If pregnancy is desired, the eggs are warmed for fertilization. the process of warming takes place in room temperature followed by a laboratory incubation.

 

SUCCESS RATES

Slow Freezing

Slow frozen eggs have a survival rate of 61 percent, i.e., only sixty one percent of eggs can survive after the process of thawing.

Vitrification

In case of vitrification, the survival rates of eggs can be as good as 85 percent. Consequently, the chances of pregnancy, can be as high as 65 percent.

 

WHY VITRIFICATION IS BETTER?

The process of vitrification is a faster one, in comparison to slow freezing. The process of vitrification takes about ten minutes, keeping apart the time required for obtaining eggs from the female body.

Higher concentrations of cryoprotectants prevent any breakage in the cell membrane.

There are less chances of ice crystal formation which ensures the cell doesn’t rupture or die.

The success rates are higher in comparison to that of slow freezing. The survival rates of eggs can be as good as 85 percent and the chances of pregnancy can be as high as 65 percent.

The process of vitrification can be used for non-inseminated eggs, too, which makes it a virtue for females with medical complications who do not have a partner while undergoing the process. Or simply, for women who want to go for it for lifestyle reasons.