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Vitrification or Cryopreservation

Cryopreservation is the freezing of biological matter to preserve it for future use, and is utilized as a method of fertility preservation. It involves cooling and storing of Sperms, Eggs and Embryos at very low temperatures to maintain their viability.

A woman’s eggs, a man’s sperm, or a fertilized embryo are all capable of being cryopreserved. When the woman or couple is ready, the eggs or the embryo, as the case may be, are thawed (Warmed)fertilized, and transferred to the uterus.
This procedure allows an individual or a couple to protect their biological reproductive material at a time it is healthiest, before age or health conditions decrease their quality or quantity. Once the materials are preserved, they may be used in future in assisted reproductive technologies (ART) to achieve a pregnancy.

Scientifically theses eggs and embryos can be frozen for multiple years without any detrimental effect on them. However, the ICMR guidelines suggest that they can be frozen for up to 5 years.

A couple may opt for Vitrification for any one of the following reasons:

  • For health reasons; for example, the need for cancer treatment that may damage reproductive abilities, degenerative reproductive system disorders,
  • Prioritization of career, educational, or personal goals.
  • The wish to delay child bearing for any other personal reason.
  • Embryo transfer is cancelled due to a number of reasons.
  • Preserving “leftover” embryos from an IVF treatment to use at a later date in case the present cycle doesn’t work or for another baby. If a patient has embryos vitrified at the clinic. They do not need to undergo egg retrieval. They can thaw the embryo and get a transfer done. Only medications to support the pregnancy need to be taken.

Why is oocyte vitrification done?

Oocyte vitrification is done in the following cases:
  • Social: Absence of the male partner so the female may want to preserve her fertility
  • Fertility preservation before taking toxic drugs for treatment like cancer. Only mature oocytes are vitrified after denudation

The process:

Vitrification is done by washing the oocytes or embryos in media within a stipulated time, once the washing is completed the embryo or eggs are loaded on a loading device and submerged immediately into liquid nitrogen. They are stored in liquid nitrogen at all times (-196c) How many embryos or oocytes can be frozen on one straw?

The number of embryos depends on the stage of their development.

  • Cleavage stage – embryos then no more than three embryos should be vitrified per straw
  • Blastocyst stage – their diameter is bigger so no more than two should be vitrified on one straw
  • For oocytes – No more than four oocytes should be frozen on one straw

Essentials for a good vitrification program

  • Embryologist trained in vitrification
  • Vitrifying only good embryos
  • Adhering to the defines number of embryos or oocytes on each straw

However, you need to be aware that sometimes even though all the precaution is taken the embryos may not survive. Embryo survival rate after vitrification is 96%

There is currently no evidence that cryopreservation negatively impacts the outcome of the child.

Frequently Asked Questions

Embryo cryopreservation, also known as embryo freezing, is typically performed at the blastocyst stage, which occurs about five to six days after fertilisation. At this stage, the embryo has developed into a hollow ball of cells and is more likely to survive the freezing and thawing process. Additionally, blastocyst-stage embryos have been shown to have higher implantation rates and lower risks of chromosomal abnormalities. However, the decision to freeze embryos at a particular stage may depend on individual circumstances and should be discussed with a healthcare provider. How long does embryo freezing last?

Embryo freezing, also known as cryopreservation, is a technique used to preserve embryos for future use. Frozen embryos can be stored for long periods of time, ranging from months to years, depending on the storage method used. The two main methods of embryo freezing are slow freezing and vitrification. Slow freezing can be used to store embryos for up to 10 years, while vitrification has been shown to result in higher survival rates and can be used for longer storage periods, up to 20 years or more.

Embryo freezing, also known as cryopreservation, is generally considered safe, but there are some potential risks and complications associated with the procedure. The most common risks of embryo freezing are damage to the embryo during the freezing and thawing process, as well as the risk of failed thawing or failed implantation after the embryo is transferred. Additionally, there is a small risk of genetic damage to the embryo during the freezing process. It is important to discuss the risks and benefits of embryo freezing with a healthcare provider.

During the egg freezing process, it is generally recommended to avoid alcohol, smoking, and drug use, as these substances can have a negative impact on egg quality and overall reproductive health. Additionally, it is important to maintain a healthy lifestyle, which includes a balanced diet, regular exercise, and stress reduction techniques. It is also important to follow any specific instructions provided by the healthcare provider, such as avoiding certain medications or activities that may interfere with the egg freezing process.

The number of eggs retrieved for egg freezing can vary depending on several factors, such as the woman age and ovarian reserve. In general, the aim is to retrieve as many mature eggs as possible in a single cycle. The ideal number of eggs for egg freezing is generally considered to be at least 10-15 mature eggs. However, some women may have a lower ovarian reserve or respond less to fertility medications, which may result in the retrieval of fewer eggs.

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