Vitrification and Slow Freezing

We live in an age and time where the miracle of life can happen in anyone’s life. Becoming a parent for couples facing infertility issues has become something more than a distant dream. With the advancement of technology, there are now tons of methods available through which couples can get pregnant artificially. Let us today discuss two options individuals can consider in this area.

Embryo and its formation

An embryo becomes a baby after going through many phases of development. An embryo, a blastocyst, and a foetus emerge from the egg. Fertilization happens when the ovaries release one egg, which usually occurs 14 days following the last menstrual cycle. The sperm quickly reaches the uterus through the fallopian tube, where the egg is washed. If fertilization is unsuccessful, the egg degenerates and passes through the uterus with the subsequent menstrual cycle. If sperm enters the egg, it forces the fertilized egg (zygote), which splits repeatedly, through the tube. In three to five days, the zygote enters the uterus.

When two eggs are released and fertilized, the pregnancy results in fraternal twins, which are two sets of twins.

Formation of Blastocyst:

By days nine or ten following fertilization, the blastocyst has attached itself to the uterine lining, generally at the top. Implantation then takes place. The wall of the blastocyst is one cell thick, except in a particular location where it is three or four cells thick. While exterior cells penetrate the uterine wall to create the placenta, inside cells grow into the embryo. Human chorionic gonadotropin is one of the hormones produced by the placenta that inhibits the ovaries from releasing eggs and promotes the development of progesterone and estrogen. Moreover, it transfers waste products, nutrition, and oxygen from the mother to the fetus. The blastocyst creates an amniotic sac, which envelops the embryo and fills it with amniotic fluid.

Formation of Embryo:

The development of both internal and exterior bodily structures occurs during the embryonic period of pregnancy. About three weeks after fertilization, or five weeks into a pregnancy, is when most organs develop. The embryo grows longer and takes on a human shape. The heart and main blood arteries expand earlier than the brain and spinal cord. All organs, including the brain and spinal cord, fully develop by ten weeks. During this phase, the majority of birth abnormalities occur, leaving the embryo susceptible to medications, radiation, and viruses. Pregnant women should refrain from taking drugs or receiving live virus immunizations unless essential to safeguard their health.

Embryo freezing:

One method for storing embryos for future use is embryo freezing. You can also freeze unfertilized eggs. The first successful pregnancy from freezing a healthy embryo occurred in the 1980s. Since then, many people have frozen embryos for various reasons, including future pregnancy, donation, medical research, or training. The process involves using hormones and medications to stimulate the production of fertile eggs, which are then extracted for fertilization in a lab or freezing. Successful fertilization may result in at least one healthy embryo, which can then be transferred to the uterus for development. The remaining embryos can be frozen and preserved for future use.

Egg freezing and embryo freezing are both different. In embryo freezing, fertilized eggs are frozen, whereas egg freezing is the freezing of unfertilized eggs.

Cryopreservation:

The primary objective of cryopreserving embryos is their future use. On the other hand, crystals may develop and explode when the water in cells freezes. Using a cryopreservation method that substitutes a cryoprotectant for the water is avoided. Before being frozen, the embryos are treated with increasing concentrations of cryoprotectant. After most of the water is removed, one of two techniques is used to reduce the embryo's temperature to its preservation stage.

1. Vitrification

2. Slow freezing

Benefits of cryopreservation:

Embryo freezing helps people get pregnant if they are facing the following:

Growing older.

shift in gender.

infertility problems.

For social or personal reasons, such as wanting to put off getting pregnant for a few years, seeking a higher degree, or managing professional obligations.

Risks:

damage done to embryos while freezing.

embryos unsuitable for freezing.

inability to conceive after thawing and implanting embryos.

A greater risk of pregnancy-related illnesses such as placenta accrete spectrum and preeclampsia.

twins, triplets, or multiple births if more than one embryo is implanted.

What is Vitrification?

The vitrification process is a quick freezing that turns the liquid inside eggs, embryos, and sperm into a solid glass state. Using conventional freezing techniques, these genetic components would gradually freeze. Damage-causing ice crystals may result from this, particularly in delicate eggs. Nevertheless, the speed at which this new technique operates prevents these ice crystals from forming.

Through vitrification, the embryo or oocyte-containing fluid protects the cells from the damaging effects of freezing. The water molecules in the cells cool so quickly that they cannot create harmful ice crystals and instead solidify into a structure resembling glass immediately.

Frozen embryo survival has increased from 60-70% to 90-95% using this freezing process (2,000-2,500C per minute), which is 7,000 times quicker than traditional slow cooling approaches.

How are Embryos vitrified?

An embryo is quickly frozen by being suspended in a drop of cryopreservation medium on a tiny instrument with a small hook. The droplet is then dropped upon a piece of metal chilled with liquid nitrogen, causing it to solidify into a bead resembling glass.

The average embryo vitrification process takes ten minutes to complete. The frozen embryos are then kept separately in a liquid nitrogen tank in a cane with a label.

Benefits of vitrification:

Following an IVF treatment, patients who have extra embryos can freeze them and try to conceive later.

Having a frozen embryo on hand eliminates the need for a whole IVF round if the fresh embryo transfer fails.

Results have improved with the transfer of thawed embryos following fast freezing: around 95% survive vitrification, and at least 40% become pregnant.

Age does not cause deterioration of frozen embryos. For instance, if you freeze an embryo at age 30 and then decide to defrost and use it at age 35, the embryo's quality and cell structure stay the same as they were at that age.

Slow freezing:

This cryopreservation method, sometimes called slow programmable freezing, was first used in the 1980s. It involves freezing the egg or embryo at a slow rate.

Slow freezing of embryos:

Cryoprotectant, or anti-freeze, is initially applied to keep the cells safe during the procedure. Once they reach the ideal freezing temperature of -196 degrees Celsius, they are progressively cooled down at 1-2 degrees Celsius per minute.

The eggs and embryos are kept in specialized containers within cylinders filled with liquid nitrogen. The biological activities inside the cell stop, but they can continue for years. When it comes time to use the eggs or embryos for IVF therapy, they can be thawed later. They must be examined to find any damage that may have occurred during the gradual freezing process. The most frequent issue with this approach was the formation of ice crystals, so vitrification was developed as an upgrade.

Which is better: vitrification or slow freezing?

Vitrification is a speedier cryopreservation method with several advantages over slow freezing. It protects eggs and embryos from cellular damage by inhibiting the production of intracellular ice. Because of the almost 90% post-thaw survival rate, the outcomes of IVF are similar to those of new cycles. It takes hours to accomplish slow freezing, yet it just takes minutes to achieve vitrification. Most IVF clinics choose vitrification because of its higher success rate and dependability, particularly regarding egg freezing. Since vitrification has been so successful, freezing eggs or embryos is no longer regarded as experimental; most clinics utilize this technique to ensure their patients have high success rates.

MMC IVF with you:

MMC IVF, the leading fertility clinic provides top-notch fertility specialists to assist couples worldwide in creating their families. We also offer medical concierge services, so we handle all the arrangements for your stay, transport, and medical care. Call us at +971 56 404 5330 to schedule an appointment or email info@mmcivf.com. We'll respond to you as soon as possible. The best thing is that before you decide, you may chat with our experts online at home. Additionally, you can ask for a second opinion about your current diagnosis and course of therapy. Contact MMC IVF and we'll arrange a time to discuss.