Pre-implantation Genetic Test


A trend towards delay in pregnancy has resulted in a drastic advancement of women in taking up IVF treatment. In such women, the proportion of embryo exceeds 60% with a greater chance of miscarriage resulting in emotional and financial hardship. Last 30 years, genetic testing has developed to figure out normal embryos with successful cycles.

Genetic testing for disease can be used by people who have a serious issue of inherited disease in their family which they do not want to pass on their newborn child. Genetic testing before pregnancy allows the transfer of healthy embryos to attain pregnancy.

An overview of Pre-Implantation Genetic Test

Pre-implantation genetic testing (PGT) in an early form of genetic testing where the experts identify the abnormal embryos and accordingly genetically normal embryos are used for the implantation process.  The genetic screening so far has become an integral part of Assisted Reproductive Technology (ART).

The technique figures genetic defects in embryos created through IVF before pregnancy.  In contrast to genetic testing, the pre-implantation genetic screening refers to a method where embryos from presumed chromosomally normal genetic parents are screened for aneuploidy.

Before proceeding, the embryos are tested in a lab. For this IVF is necessary even if the couple has no infertility issue. The tested embryos after analyzing the condition are placed back in the womb for development. Previously, the embryos were usually transferred between two to six days after genetic testing pregnancy but now the embryos are frozen for the later stage.

Recommendations to pre-implantation genetic testing

Pre-implantation testing is recommended to the followings:

  • Female who have advanced maternal age.
  • Women facing continuous miscarriage due to serious genetic conditions.
  • Couple who has a child with any genetic issue and want to avoid in the next child.
  • Pair with a strong family history with serious genetic conditions.
  • Patients with chromosome problems.
  • Women experiencing unrecognized embryonic loss and are labeled clinically infertile.

 Genetic screening is performed in a couple who has no increased risk of bearing a child with an inherited genetic disease.

Pre-implantation genetic screening applications

  • Re-arrangement of chromosomes – In the first trimester of pregnancy, the chromosomal abnormalities are present up to 0.9% while the associated miscarriage remains 50-60%. These aneuploidies are the result of non-disjunction event. Though most of the women are blessed with normal phenotypes, they too frequently suffer from repeated abortion or fertility issues, high delivery risk, congenital anomalies, or intellectual disability. Studies have repeatedly shown that genetic screening tests improve pregnancy outcomes, especially in patients dealing with frequent pregnancy losses.
  • Genetic disorders – Identification of single-gene disorders such as myotonic dystrophy type I, neurofibromatosis, thalassemia/sickle cell disorders, X-linked recessive diseases, hemophilia A and B, Fragile X syndrome and Duchenne/Becker muscular dystrophy.
  • Genetic testing – human leukocyte antigen (HLA)Patients suffering from leukemia, sickle cell anemia, hypo immunoglobulin syndromes, or beta-thalassemia may benefit from the genetic screening with cell transplantation by using matched HLA.  Usually, pre-genetic testing is useful when a child has a non-genetic disease such as leukemia where the parents are looking to have PGD with HLA. Likewise, if the child has a heritable disorder, the parents can seek screening tests to avoid another infected child.

Types of genetic screening

Pre-implantation genetic screening provides detailed information on an individual overall health status. It includes:

  • DNA genetic testing – Genetic diagnosis is done to establish paternity before or after birth. If the female had multiple partners the screening can be done to identify the biological father.
  • Genetic blood test – On the prenatal care, blood test analyzes the blood type, Rh factor, hemoglobin level, glucose, and iron level.
  • Genealogy test – This test, finds out the ancestral genome, and ethnicity.
  • Prenatal genetic screening – It detects the changes in chromosomes or fetus during the pregnancy. In a few cases, prenatal testing helps to determine the patient’s uncertainty and make decision on pregnancy.
  • Fetal non-stress test – The fetal genetic testing indicates the proper flow of blood and oxygen to a fetus’s in an adequate manner.
  • Carrier testing – This testing identifies people carrying a copy of gene mutation causing genetic disorder. The testing is recommended to parents carrying a history of genetic disorder with an increased condition of specific genetic conditions. If both the parents are tested it provides information to the parents of the associated risk giving birth to a child holding genetic condition.
  • IVF genetic testing– A type of screening that detects genetic changes in embryos by testing a small number of cells extracted from the embryos. The genetic testing cost is affordable, but if the complexity rises the cost may increase.

Process for genetic screening before pregnancy

For genetic disease screening one or more cells are taken from the embryo for genetic profile testing while the embryos are growing in a laboratory. The testing can be done in different stages with several techniques such as microarray, fluorescent in situ hybridization (FISH) and single- nucleotide polymorphism (SNP).  The methods of genetic disease screening involve:

  1.  Artificial stimulation of ovaries – Hormones are used to produce several eggs. A large number of embryos are likely to get affected by the chromosome abnormality; few numbers of embryos are created for a successful chance.
  2.  Collection of oocytes – During the egg retrieval process, the eggs are removed for the inspection to determine its maturity level and normal appearance.
  3. Insemination process – During the Pre-implantation genetic testing fertilization is done either with invitro-fertility fertilization (IVF) or intracytoplasmic sperm injection (ICSI).
  4. Fertilization – After the insemination, doctor shall carefully examine each egg to evaluate its fertilization.
  5. Biopsy of an embryo – For nearly 5-6 days the embryos are grown inside the laboratory. At this stage, the trophectoderm biopsy is performed.
  6. Embryo genetic testing – Screening embryos for genetic disorders, the cells are tested to examine the abnormalities and the causes of genetic conditions. Genetic testing embryos before implantation helps the pair decide the treatment process during the pregnancy.
  7. Transfer of embryos - Genetic screening of embryos test the specific genetic condition before getting implanted into the uterus. Usually, one embryo gets transferred to avoid multiple births. Any suitable remains of embryo shall be frozen for later use.  While those embryos affected by the genetic disease are either perished or asked to be donated for training or research.
  8. Pregnancy test – After 12 days of genetic testing and screening of an embryo, a woman is given a pregnancy test. A positive test means the successful implantation of an embryo.

Searching for the best genetic testing?  Well, to understand that one must visit Vatsalya, the fertility clinic, as there are cases where patients may require preconception genetic testing with other fertility related tests. Pre-implantation genetic diagnosis cost may vary according to the patient’s fertility-status.

Benefits of genetic testing before pregnancy

Chromosome abnormalities are generally responsible for 70 percent of miscarriage in early pregnancy. Hence, pre-implantation genetic screening. Additional benefits of genetic screening include:

  • Enhances the chances of a healthy pregnancy.
  • Higher pregnancy rates after embryo transfer.
  • Fewer cycles of IVF treatment.
  • Allows single transfer with the best chances of implantation.
  • Reduces the risk of multiple pregnancies.
  • Avoids the issue of preterm birth, abnormal placental function, and preeclampsia.
  • Reduction of the time interval between IVF cycles.

The risk associated with genetic screening pregnancy

Several studies have concluded that no major side effects appear during the genetic testing of inherited disease and in genetic testing baby, however,

  • The babies born through IVF are likely to weigh less or born prematurely.
  • Pre-implantation of genetic testing requires IVF, which involves the risk of minor birth defects which is not related to a genetic test, and ovarian hyperstimulation syndrome.
  • Possibilities of harming the embryos.
  • Negative results can lead to possible miscarriage and limit the chances of a healthy pregnancy.
  • Testing of genetic disorders may not possibly screen all genetic diseases or disorders.

So far no longer outcomes are known from the preconception genetic testing. Though, it is important to continuously monitor the child’s progress born following pre-implantation genetic disorder.

Vatsalya is Nepal’s most reliable and trusted genetic testing center to perform genetic screening pregnancy in a woman. The fertility center aims to assist its client from the scratch till attaining healthy pregnancy. Hence, individuals seeking to understand the detailed genetic screening procedure and genetic testing pregnancy cost, you can contact us!

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