Awareness about Embryo Biopsy, PGD & PGS

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Understanding Embryo Biopsy

Picking cells from IVF embryo is called Embryo Biopsy. The cells picked are sent laboratory for DNA analysis. This biopsy is usually opted by the couples who undergo the IVF procedure. This biopsy helps in genetic screening of the Embryo.

Vitro fertilization basically fertilizes the female egg in an incubating dish. This process leads to creation of multiple embryos during the process. Before implanting the Embryo, the incubated embryos are assessed on the basis of development rate and potency.

Know the process of Embryo Biopsy

  • On the Day 3 of Embryo Development a small opening is created using laser in the thick transparent membrane called Zona Pellucida. This also expedites the hatching process which starts from Day 5.
  • With hatching, the trophectoderm starts protruding through zona pellucida.
  • With the use of specialized advanced micro tools and laser, the embryo is kept hold of and cells are taken from this protruding section. Extensive care is taken to keep the embryo cells safe as they will develop into a foetus.
  • All the embryos developed during IVF undergo this process. Post biopsy, these are frozen and stored.

Biopsy of 3rd day vs 5th day

Biopsy can also be conducted on the 3rd day of embryo development. Herein, out of the 8 cell embryo 1-2 blastomeres are removed. This procedure is carried out by creating an incision of a hole in the shell and the embryo can be deprived of a major part of total mass. This decreases the implantation rate.. Only a single cell is required for analysis, post which the embryos are not frozen because the screening reports are out before the implant.

In the Biopsy on day 05 biopsy the cells are removed from the placenta portion. This membrane does not become part of the foetus but forms the supporting structures around the foetus like the placenta.This portion is the exterior embryo, therefore does not impacts the main structure that develops into a foetus. The implantation rate is higher in this process. This biopsy gives more accurate analysis, as there is more genetic DNA available for screening.

Pre-implantation Genetic Diagnosis (PGD)

PGD is a procedure that is carried out along with the In vitro fertilization (IVF). PGD involves taking a single cell from the IVF embryo and testing it for specific genetic conditions. This process helps to diagnose more than 1000 types of single gene mutations. PGD is usually advisable to patients who have had any of the conditions like infertility, history of miscarriages, higher age of patient, previous IVF failures, any inherited genetic disorders, etc.

Pre-implantation Genetic Screening (PGS)

It is also called Comprehensive Chromosome Screening, One of the most potent tools to test the overall chromosome status in embryos is PGS. This process traces abnormalities in the chromosomal configuration of the embryo that may lead to various genetic disorders. A human cell contains 46 chromosomes which carry genetic information in the form of DNA. A growing foetus receives 23 chromosomes from each parent. If the egg or sperm possess a missing or an extra chromosome, then the embryo in formation also have the same chromosome as missing or extra. This condition is known as aneuploidy and can be diagnosed in PGS.

Benefits                           

  • This process filters the more potent embryo out of the abnormal embryos. This helps improve the success rate for IVF.
  • It makes the expected parents aware about the genetic content of embryo before being implanted to uterus.
  • Parents who carry the single gene mutations can avoid passing these to the offspring.
  • Parenthood at an age after 35 can diagnose chances of development of abnormal fetal and can be reduced marginally.

Risks Involved

The risks involved in these procedures is very minimal in comparison to the benefits attained. Also to understand that any procedure of micro-manipulation will have a certain chances of failure.

Although, advanced techniques, tools, experts, medical specialist of this domain can help couples go through the procedures successfully and conceive through IVF.

About author

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Dr. Manju Gupta

Dr. Manju Gupta completed MS (Obstetrics & Gynaecology) and senior residency from VMMC, Safdarjang Hospital, New Delhi. Dr. Gupta is particularly interested in fetal medicine and high risk obstetrics. She also has three research papers published in national and international journals to her credit. Presently, she is assocaited with Jaypee Hospital, Noida

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