Preimplantation genetic testing, PGT-A for chromosomal abnormalities, provides a pre-pregnancy plan and can detect abnormal chromosomes in embryos
Preimplantation genetic testing, PGT, is a technique used in conjunction with IVF to increase the likelihood of transferring chromosomally normal embryos into your uterus. Texas Fertility Center works closely with Ovation® Fertility, our partner IVF lab, as well as the leading genetics labs in the country, to provide this essential fertility treatment to specific patient populations.
Individuals and couples who should consider PGT-A
- Women experiencing recurrent miscarriages
- Women with repeated implantation failure with IVF
- Couples in which the woman has advanced maternal age
We all have 22 pairs of chromosomes (autosomes) and one pair of chromosomes (X and Y) that determines our sex. When the sperm fertilizes an egg, the mother will contribute one chromosome to the embryo’s pair, and the father will provide the complementary chromosome.
Problems occur when an embryo has extra or missing chromosomes (aneuploidy) or a part of one chromosome breaks off and reattaches in a different place (a “translocation”) on another chromosome.
Understanding the PGT-A Process
When a couple decides to have PGT conducted, they first undergo a routine IVF procedure, with ovarian stimulation, egg retrieval, fertilization, and embryonic culture (growth) in the laboratory. But then, before their excellent-quality embryos are frozen, a small sample of 6-8 cells is gently removed from each embryo on Day 5, 6, or 7 following the egg retrieval. Although several different mechanisms can be used to biopsy the embryos, we believe that using a laser allows us to take the best-quality sample with the least risk of damage to the embryo. Following biopsy, the embryos are frozen, the samples are sent to a genetics laboratory, and we await the results, which usually takes about 7-10 days.
PGT testing allows us to determine which embryos have a normal number of chromosomes, and therefore an excellent chance to become a healthy baby, and which embryos have an abnormal number of chromosomes and are therefore typically unable to develop normally. This process has been shown to result in a significantly higher chance for pregnancy and delivery, as well as a reduced risk of miscarriage. In addition, as we know that the chance for pregnancy is higher for PGT-tested embryos, we usually only transfer a single embryo, reducing if not eliminating the risk of multiple gestation.
PGT-A can identify the cause of recurrent pregnancy loss
Our Austin fertility physicians may employ PGT to evaluate embryos from couples who have experienced recurrent pregnancy loss. The most common reason for early (typically first trimester) pregnancy loss is genetic, and this is usually associated with the embryo having either too many or too few chromosomes, a condition referred to as aneuploidy.
Some conditions that result from aneuploidy include Down’s syndrome and Turner’s syndrome. These two abnormalities are the most common examples of aneuploidy, and typically produce abnormal pregnancies that usually spontaneously miscarry.
To inquire about the benefits of preimplantation genetic testing and applications for your unique situation, please contact the care coordinators at Texas Fertility Center.