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Preimplantation Genetic Testing, PGT

Preimplantation genetic testing increases the odds of IVF success

Every patient who visits Texas Fertility Center (TFC) wants the best chance of bringing home a healthy baby. Preimplantation genetic testing (PGT) can make this possible for a wide range of patients, including women over 35, couples who have faced recurrent miscarriage and IVF cycle failure, and women and men with inheritable genetic illnesses. Our San Antonio infertility doctor Erika Munch MD offers patients two types of genetic testing to make this possible.

A look at two types of preimplantation genetic testing

Depending on a patient’s needs and wishes, our San Antonio infertility doctor may recommend PGT-A or PGT-M. The first test screens for chromosomal abnormalities (ie. abnormalities in the number of chromosomes present in the cells), while the second can detect the presence of microscopic defects in specific genes. Both forms of testing are extremely accurate, so they can help ensure IVF success and the delivery of a healthy baby.

All patients can benefit from PGT-A. However, it is especially helpful for women over 35 and patients who have experienced IVF failure or multiple miscarriages. As for PGT-M, Dr. Munch will recommend it to couples who both have or carry an inheritable genetic illness.

How the process of genetic testing works for patients

Both forms of preimplantation genetic testing occur during an IVF cycle, between the steps of fertilization and embryo transfer. A healthy embryo reaches the blastocyst stage between Days 5 to 7 of development. At that time, the embryologists in our IVF laboratory use a microscopic laser to make a tiny hole in the outer membrane that surrounds the blastocyst. They will then carefully remove three to five of the approximately 128 cells that make up the blastocyst.

Our embryologists will then freeze the biopsied cells at 320 degrees below zero and send them by courier to a genetic testing laboratory.

  • If patients selected PGT-A, the specialists at the genetics laboratory will look at the chromosomal makeup of the biopsied cells from each embryo. The goal is to ensure that it has 46 chromosomes. By transferring embryos with the normal number of chromosomes, our clinic has ongoing pregnancy rates of 60% to 70% per embryo transferred.
  • On the other hand, PGT-M evaluates each embryo to determine whether it carries a specific genetic disorder, such as sickle cell disease, Tay Sachs, cystic fibrosis or spinal muscular atrophy.

Five to seven business days after sending the biopsied cells to the laboratory, Dr. Munch will receive the test results and learn which embryos are healthy. Our San Antonio infertility doctor will use this information to transfer the embryo that has the best chance of developing into a healthy baby.

Contact us to schedule a consultation with Dr. Munch. She is happy to discuss preimplantation genetic testing with you.