In the field of assisted reproductive technology, the United States has consistently been at the forefront, with the third generation IVF technology being one of its proud achievements. The third generation IVF technology includes Preimplantation Genetic Testing for Aneuploidy (PGT-A) and Preimplantation Genetic Testing for Monogenic Disorders (PGT-M), further enhancing the success rates of IVF while reducing the risk of genetic diseases.

What are PGT-A and PGT-M in IVF?

In 2017, international academic organizations such as the American Society for Reproductive Medicine (ASRM) and the European Society of Human Reproduction and Embryology (ESHRE) jointly recommended using PGT to describe “third-generation IVF.” To differentiate the various applications of PGT, three different letters were suggested: PGT-A, PGT-SR, and PGT-M. In simple terms, PGT technology encompasses the previous PGS (Preimplantation Genetic Screening) and PGD (Preimplantation Genetic Diagnosis), with PGT-A equivalent to the former PGS, while PGT-M and PGT-SR together correspond to the previous PGD.

PGT-A is primarily used to screen for chromosomal abnormalities in embryos, especially for older women, as the risk of chromosomal abnormalities increases with age. Through PGT-A, these abnormalities can be detected before embryo implantation, increasing the success rate of pregnancy and reducing the risk of miscarriage. This method identifies the presence of aneuploidy or abnormal chromosomes by examining the chromosomal composition of embryos.

PGT-M is used to detect abnormalities caused by single-gene genetic diseases. This technology can screen embryos that do not carry pathogenic genes, preventing genetic defects and helping couples have healthy offspring. Unlike chromosomal abnormalities, single-gene genetic diseases are caused by mutations in a single gene. Due to the complexity of the human genome, screening for single-gene genetic diseases requires more precise techniques.

How is IVF with PGT conducted in the United States?

  • Ovulation Induction/Egg Retrieval

Before entering the IVF cycle, U.S. IVF specialists analyze the medical reports provided by women and develop individualized treatment plans for each person. They use medications, including hormones, to regulate the menstrual cycle. On the second day of the menstrual cycle, medication for ovulation induction begins. The use of medications is certified by the U.S. Food and Drug Administration, natural, and without side effects, minimizing the risk of ovarian hyperstimulation syndrome. Throughout the medication period, specialists monitor hormone levels and follicle development through ultrasound. If there is any abnormal response to the medications, adjustments are made promptly to ensure the safety and health of women. Egg retrieval is a quick procedure, taking only 10-15 minutes, and is entirely safe and painless for women.

  • ICSI (Intracytoplasmic Sperm Injection) for Fertilization

IVF specialists retrieve eggs and sperm and use Intracytoplasmic Sperm Injection (ICSI) to select high-quality sperm from the many sperm from the male. Using high-powered microscopy, a perfect sperm is chosen and injected into the egg. This method effectively addresses fertilization difficulties and, for women with lower egg quality, ensures the use of a relatively superior sperm, avoiding wasting eggs or combining with problematic sperm to improve future embryo implantation rates.

  • PGT Technology for Embryo Testing

IVF specialists use third-generation PGT technology to screen embryos for chromosomal abnormalities, such as balanced translocations, Robertsonian translocations, inversions, etc. This helps avoid infertility, miscarriage, fetal abnormalities, and other complications during the reproductive process. Additionally, genetic diagnosis allows U.S. fertility centers to effectively rule out nearly 300 genetic diseases, such as congenital deafness, thalassemia, Down syndrome, color blindness, hepatitis B, etc. Babies born through this technology are not only comparable to naturally conceived babies but are also healthier and safer, achieving the goal of eugenics. The success rate of IVF in U.S. fertility centers is 89.8%, providing the possibility of having a baby for women of advanced maternal age, those experiencing infertility, and individuals with specific needs.

  • Embryo Transfer

The uterus is the environment in which embryos depend for survival, and only a favorable uterine environment ensures the smooth growth of the fetus. Therefore, before the transfer, IVF specialists first regulate the woman’s body with medication to improve the uterine environment. When the uterine environment meets specific criteria, such as endometrial thickness between 8-12mm, abundant blood flow, good cell division, balanced hormone levels, and normal uterine cavity formation, specialists implant healthy embryos into the uterus at a specific location. This completes the subsequent processes of implantation, pregnancy, and childbirth, ensuring the safe birth of the baby.

After confirming a pregnancy reaction, the U.S. service team continues to monitor. IVF specialists recommend that expectant mothers continue to take pregnancy-supporting medication for about 12 days, typically choosing progesterone. The choice of medication form (sublingual, vaginal, or intramuscular injection) depends on the woman’s physical condition.