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Understanding Genetics

Chromosomes are small structures made up of protein and a single molecule of DNA. The human body needs 46 chromosomes: 23 from an egg and 23 from sperm. It’s important to understand that both chromosomes and genes play a significant role in the conception and can affect the health of your baby.

Sometimes, when chromosomal abnormalities occur, it may cause miscarriages, inability to conceive, and genetic diseases. Fortunately, we have advanced in reproductive genetics and can now screen embryos to detect chromosomal abnormalities and gene mutations.

In vitro fertilization (IVF) allows us to select the highest quality chromosomally normal embryos possible to reduce possibilities of future miscarriage and implantation failure.

IVF gives you the best chance to deliver a healthy baby.

PREIMPLANTATION GENETIC TESTING

PGT-A (Preimplantation Genetic Testing for Aneuploidies), is when a biopsy of cells from an embryo is removed to determine if it contains a normal number of 23 pairs of chromosomes.

PGT-A gives information about embryos’ genetic health to help us select the best embryo for implantation and is only tested on a Blastocyst which is the last stage of IVF embryology development. We recommend genetic testing for women ages 35 and older, whose eggs are more at risk for chromosomal abnormalities, history of multiple miscarriages, or repeated implantation failure.

TYPES OF RESULTS

Normal (Euploid)

  • These embryos have 46 chromosomes in each cell, and this is the result you want to see.
  • These embryos are the best candidates for a successful transfer.

Abnormal (Aneuploid)

  • This shows an abnormal number of chromosomes in the cells of the biopsied sample.
  • Sometimes this means an embryo has an extra chromosome or a missing chromosome. These embryos typically cannot implant or may cause a miscarriage.

Partial/Segmental

  • This means that there is an extra or missing piece of a chromosome. For example, it’s like a book with an extra or missing chapter.
  • The success of implantation comes down to which specific chromosome pieces are extra or missing.

Mosaicism

  • Abnormalities don’t mean an embryo wouldn’t survive after it’s been transferred, and that’s where mosaicism comes in. Mosaic embryos are those that are neither fully normal nor fully abnormal.
  • Instead, they include some abnormal cells which often correct or repair themselves during gestation. However, mosaic embryos implant less and miscarry more than a normal embryo, but these embryos can still lead to a healthy birth. Read more on Mosaic Embryos here.

PGT-A GENDER SELECTION

Through PGT-A testing, the sex chromosomes of an embryo can be analyzed. On a PGT- A report, you have the option to view the gender of the embryos or ask that the gender is removed from the report.

  • XX Female
  • XY Male

ORIGIN OF ANEUPLOIDY

Aneuploidy is an abnormal number of chromosomes in an embryo. For example, an embryo with 45 or 47 chromosomes versus the normal 46. When an embryo is abnormal, this may cause failed implantation, miscarriage, or stalled embryo development. An aneuploidy can originate from sperm or the egg.

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