Preimplantation Genetic Testing

Preimplantation Genetic Testing – Aneuploidy (PGT-A) helps identify embryos that are most likely to implant and result in a successful pregnancy and also reduces the chance of having a child with extra or missing chromosomes which could cause disorders such as Down syndrome During PGT-A, embryos created through IVF are biopsied and screened for all 46 chromosomes.

PGT-A also allows for family balancing (elective gender selection) as it identifies the chromosomal sex of the embryo (XX or XY) and this information is provided for those who wish to have it.

Many patients undergoing IVF choose to utilize PGT-A with their cycle. At Advanced Fertility Care, about 95% of our IVF patients decide to use PGT-A as a part of their treatment plan. Below are common cases for which PGT-A will be recommended:

• Later Maternal Age: All women have a risk to have a pregnancy with a chromosome abnormality. This risk increases as a person’s age increases. Prenatal diagnosis by chorionic villus sampling (CVS) or amniocentesis to test for chromosome abnormalities, such as Down syndrome, is also available post-conception, however, PGT-A enables patients to determine risk prior to implantation of embryos. There are many recent and ongoing studies that have indicated a significant increase in overall pregnancy outcomes for women over age 35 who utilize PGT-A technology in conjunction with IVF. For women under age 35, PGT-A is still an option, especially for family balancing reasons.
  For those with a good prognosis, the overall benefit to increased pregnancy outcomes is still considered controversial. If you are interested in considering PGT-A with IVF, we encourage an open discussion with your physician regarding the pros and cons for your particular situations
• Recurrent Pregnancy Loss: About 50% of first trimester miscarriages are due to a chromosome abnormality. This may be related to a woman’s age or a rearrangement in a parent’s chromosomes that predisposes the couple to conceive pregnancies with chromosome abnormalities. PGT-A can be performed for either of these possibilities.
• Prior Pregnancy With Chromosome Abnormality: Patients that have had a previous chromosomally abnormal pregnancy have an elevated risk for a similar problem to occur again in any subsequent pregnancy regardless of maternal age.
• Several Failed IVF Cycles: Some cases of IVF failure are due to the transfer of embryos with chromosome abnormalities. PGT for aneuploidy minimizes the likelihood of a chromosome abnormality in a future pregnancy and increases the chance of achieving an ongoing successful pregnancy.
• Family Balancing (also known as Sex Selection): For families that wish to have additional children of a particular gender after already having a previous child, PGT-A allows for the selection of embryos to transfer based on gender. While not perfect, embryo biopsy with genetic chromosome determination prior to the transfer of embryos can allow families a choice in how they expand the family.

Preimplantation genetic testing for monogenic disorders (PGT-M) is testing administered on embryos that can determine whether a heritable genetic mutation is present. PGT-M was previously called preimplantation genetic diagnosis (PGD). This test looks for diseases caused by a mutation in a single gene, and it is offered to families with a known genetic mutation. That risk may have been discovered through routine genetic screening, such as carrier screening, or because one parent or family member already has a known genetic diagnosis.

Not all patients that undergo IVF need PGT-M. There are a number of factors that help determine whether genetic embryo screening may be of benefit. PGT-M is only offered to those with the possibility of passing on an inherited genetic condition.

PGT-M can benefit those with a known family history of a genetic disease or for structural chromosome rearrangement or particular genetic diseases such as Cystic Fibrosis, Huntington’s Disease, and Tay Sach’s Disease. There are actually hundreds of known genetic diseases which we are able to screen for and this number is increasing all the time as the human genome project continues.

Patients who need PGT-A or PGT-M will undergo a typical IVF cycle at Advanced Fertility Care. After the patient’s eggs are retrieved, they are fertilized with the husband’s or donor sperm in the laboratory. The lab waits for fertilization to occur and lets the embryos develop for 5 to 6 days into the 80-100 cell blastocyst stage. At the blastocyst stage, our embryologist will remove three to four cells from each embryo after creating a precise microscopic hole in the outer shell with a laser (embryo biopsy) and then prep these cells for secure transport to a specialized genetic reference lab for the chromosomal analysis. The embryo-specific results will then be communicated back to the embryologist and physicians at Advanced Fertility Care.

Once chromosomally normal embryos are confirmed, patients will then be coordinated for a frozen embryo transfer after appropriate ovarian suppression and uterine preparation using hormonal stimulation. The frozen embryo transfer can occur as soon as 5-6 weeks after initial egg retrieval but this is dependent on several factors. In most cases, Advanced Fertility Care Physicians will subsequently only transfer at the most two blastocysts and in most cases, recommend the transfer of one chromosomally tested normal blastocyst in order to avoid the increased risk of higher-order multiples.

In addition to the cost of the IVF procedure used to retrieve eggs and create the embryos for testing, there are two additional components that contribute to the overall costs of performing genetic testing on embryos. The first cost is the actual cost of the technique and time for the embryologist to biopsy (remove cells from) the embryos. The second cost is that of the genetic analysis of the cells that are sent to the genetics laboratory.

Since every situation may be unique, we encourage you to call our office in order to discuss the costs that would pertain to your specific situation.